2x = 64
2x - 2 = 30
18 : ( x - 6 ) = 3
3x - 1 = 80
240 : [ 2x - 4 ] = 60
2x = 64
2x - 2 = 30
18 : ( x - 6 ) = 3
3x - 1 = 80
240 : [ 2x - 4 ] = 60
143 - 53 - x = 33 x 20
2 mũ 6 x bằng 6
2 mũ 5 trừ 2 bằng 30 x = 5
x bằng 12
x bằng 4
x= 4
\(2^x=64\Leftrightarrow2^x=2^6\Leftrightarrow x=6\)
\(2^x-2=30\Leftrightarrow2^x=32\Leftrightarrow2^x=2^5\Leftrightarrow x=5\)
\(18:\left(x-6\right)=3\Leftrightarrow x-6=6\Leftrightarrow x=6+6=12\)
\(3^x-1=80\Leftrightarrow3^x=81\Leftrightarrow3^x=3^4\Leftrightarrow x=4\)
\(240:\left(2x-4\right)=60\Leftrightarrow2x-4=4\Leftrightarrow2x=8\Leftrightarrow x=4\)
\(143-5^{3-x}=3^3\times2^0\Leftrightarrow143-5^{3-x}=27\times1\)
\(\Leftrightarrow143-5^{3-x}=27\Leftrightarrow5^{3-x}=143-27=116\)
mà \(5^{3-x}\ne116\Leftrightarrow x\in\varnothing\)
Vậy: \(x\in\varnothing\)
Nhớ k cho mình nhé! Thank you!!!
\(2^x=64\)
\(2^x=2^6\)
\(\Rightarrow x=6\)
\(2^x-2=30\)
\(2^x=30+2\Rightarrow2^x=32\)
\(\Rightarrow2^x=2^5\)
\(\Rightarrow x=5\)
3x-1=80
3x=80+1
3x=81
3x=34
=> x=4
240:[2x-4]=60
[2x-4]=240:60
[2x-4]=4
2x=4+4
2x=8
x=8:2
x=4
Ys cuối bạn tự làm nha dễ mà.
1) 4x-(2x-5)=21
2) 14x+5=8x+10
3) 15+5x=3x+30
4) 2x-5=15-3x
5) 2(3x+5)+3(x+1)=6x+20
6) 4(x-3)+5(x-3)=18
1) 4x-(2x-5)=21
4x-2x+5=21
2x+5=21
2x=21 -5
2x=16
x=16/2
x=8
2)14x+5=8x+10
14x-8x=10-5
6x=5
x=5/6
3) 15+5x=3x+30
5x-3x=30-15
2x=15
x=15/2
Vậy x=15/2
Giải phương trình:
4. (2x+7)(x+3)2(2x+5)=18
5. (x2-3x+2)(2x-3)(2x-5)=30
6. (x2+3x+2)(x2+7x+12)=24
4.
\((2x+7)(x+3)^2(2x+5)=18\)
\(\Leftrightarrow [(2x+7)(2x+5)](x+3)^2=18\)
\(\Leftrightarrow (4x^2+24x+35)(x^2+6x+9)=18\)
\(\Leftrightarrow [4(x^2+6x+9)-1](x^2+6x+9)=18\)
\(\Leftrightarrow (4a-1)a=18\) (đặt \(x^2+6x+9=a\) )
\(\Leftrightarrow 4a^2-a-18=0\)
\(\Leftrightarrow (4a-9)(a+2)=0\Rightarrow \left[\begin{matrix} a=\frac{9}{4}\\ a=-2\end{matrix}\right.\)
Nếu \(a=x^2+6x+9=\frac{9}{4}\Leftrightarrow (x+3)^2=\frac{9}{4}\)
\(\Rightarrow \left[\begin{matrix} x+3=\frac{3}{2}\\ x+3=\frac{-3}{2}\end{matrix}\right.\Rightarrow \left[\begin{matrix} x=\frac{-3}{2}\\ x=\frac{-9}{2}\end{matrix}\right.\)
Nếu \(a=x^2+6x+9=-2\Leftrightarrow (x+3)^2=-2< 0\) (vô lý)
Vậy ............
5.
PT \(\Leftrightarrow (x-1)(x-2)(2x-3)(2x-5)=30\)
\(\Leftrightarrow [(x-1)(2x-5)][(x-2)(2x-3)]=30\)
\(\Leftrightarrow (2x^2-7x+5)(2x^2-7x+6)=30\)
Đặt \(2x^2-7x+5=a\) thì:
PT \(\Leftrightarrow a(a+1)=30\)
\(\Leftrightarrow a^2+a-30=0\)
\(\Leftrightarrow (a-5)(a+6)=0\Rightarrow \left[\begin{matrix} a-5=0\\ a+6=0\end{matrix}\right.\)
Nếu \(a-5=0\Leftrightarrow 2x^2-7x=0\Leftrightarrow x(2x-7)=0\)
\(\Rightarrow \left[\begin{matrix} x=0\\ x=\frac{7}{2}\end{matrix}\right.\)
Nếu \(a+6=0\Leftrightarrow 2x^2-7x+11=0\)
\(\Leftrightarrow 2(x-\frac{7}{4})^2+\frac{39}{8}=0\Leftrightarrow 2(x-\frac{7}{4})^2=-\frac{39}{8}<0\) (vô lý)
Vậy...........
6.
PT\(\Leftrightarrow (x+1)(x+2)(x+3)(x+4)=24\)
\(\Leftrightarrow [(x+1)(x+4)][(x+2)(x+3)]=24\)
\(\Leftrightarrow (x^2+5x+4)(x^2+5x+6)=24\)
\(\Leftrightarrow (a+4)(a+6)=24\) (đặt \(x^2+5x=a\) )
\(\Leftrightarrow a^2+10a=0\Leftrightarrow a(a+10)=0\Rightarrow \left[\begin{matrix} a=0\\ a+10=0\end{matrix}\right.\)
Nếu \(a=0\Leftrightarrow x^2+5x=0\Leftrightarrow x(x+5)=0\Leftrightarrow \left[\begin{matrix} x=0\\ x=-5\end{matrix}\right.\)
Nếu \(a+10=0\Leftrightarrow x^2+5x+10=0\Leftrightarrow (x+\frac{5}{2})^2+\frac{15}{4}=0\)
\(\Leftrightarrow (x+\frac{5}{2})^2=-\frac{15}{4}\) (vô lý)
Vậy...........
Tìm x biết :
a, 4.(18 - 5x) - 12.(3x - 7) = 15.(2x - 16) - 6(x + 14)
b, 5.(3x + 5) - 4.(2x - 3) = 5x + 3.(2x + 12) + 1
c, 2.(5x - 8) - 3.(4x - 5) = 4.(3x - 4) + 11
d, (3x + 2)(2x + 9) - (x + 2)(6x + 1) = (x + 1) - (x - 6)
e, (8x - 3)(3x + 2) - (4x + 7)(x + 4)= (2x + 1)(5x - 1) - 33
Noob ơi, bạn phải đưa vào máy tính ý solve cái là ra x luôn, chỉ tội là đợi hơi lâu
a, 4.(18 - 5x) - 12(3x - 7) = 15(2x - 16) - 6(x + 14)
=> 72 - 20x - 36x + 84 = 30x - 240 - 6x - 84
=> (72 + 84) + (-20x - 36x) = (30x - 6x) + (-240 - 84)
=> 156 - 56x = 24x - 324
=> 24x + 56x = 324 + 156
=> 80x = 480
=> x = 480 : 80 = 6
Vậy x = 6
b, 5(3x + 5) - 4(2x - 3) = 5x + 3(2x + 12) + 1
=> 15x + 25 - 8x + 12 = 5x + 6x + 36 + 1
=> (15x - 8x) + (25 + 12) = 11x + 37
=> 7x + 37 = 11x + 37
=> 11x - 7x = 0
=> x = 0
a) x+1/2x-6-4/2x-6 b) 3x-4/6x+3-x-5/6x+3
c) x-1/x-3-3x-8/3-x+3-2x/x-3 d) 3/x+5-5/x-7
e) 3/x+5-5/x-7 f) 2/x-2+3/x+2+5x-18/x2-4
1: 3/x+1 + 2/x+2 = 5x+4/x2+ 3x + 2
2: 2/3x + 1 - 15/6x2-x-1 = 3/2x - 1
3: 9/3x - 1 - 5-x/3x2-4x+1 = 4/x+ 1
4:5/x - 2 + 2/x+4 = 3x/x2 + 2x - 8
5: 4/x+6 + 1/x - 3 = 9/x2 + 3x - 18
6:x/x-3 - 2x2 +9/2x2 - 3x - 9= 1/2x + 3
\(\frac{3}{x+1}+\frac{2}{x+2}=\frac{5x+4}{x^2+3x+2}.\)ĐKXĐ: \(x\ne-1;-2\)
\(\Leftrightarrow\frac{3\left(x+2\right)}{\left(x+1\right)\left(x+2\right)}+\frac{2\left(x+1\right)}{\left(x+1\right)\left(x+2\right)}=\frac{5x+4}{\left(x+1\right)\left(x+2\right)}\)
\(\Leftrightarrow3x+6+2x+2=5x+4\)
\(\Leftrightarrow3x+2x-5x=-6-2+4\)
\(\Leftrightarrow0x=-4\)
=> PT vô nghiệm
\(2;\frac{2}{3x-1}-\frac{15}{6x^2-x-1}=\frac{3}{2x-1}\)
\(\Leftrightarrow\frac{2\left(2x-1\right)}{\left(2x-1\right)\left(3x-1\right)}-\frac{15}{6x^2+3x-2x-1}=\frac{3\left(3x-1\right)}{\left(2x-1\right)\left(3x-1\right)}\)
\(\Leftrightarrow\frac{4x-2-15}{\left(2x-1\right)\left(3x-1\right)}=\frac{9x-3}{\left(2x-1\right)\left(3x-1\right)}\)
\(\Leftrightarrow4x-2-15=9x-3\)
\(\Leftrightarrow4x-9x=2+15-3\)
\(\Leftrightarrow-5x=14\)
.....
mấy cái này mẫu nào dài cậu phân tích ra :
VD : câu 3 : \(3x^2-4x+1\)
\(=3x^2-3x-x+1\)
\(=3x\left(x-1\right)-\left(x-1\right)\)
\(=\left(3x-1\right)\left(x-1\right)\)
r bắt đầu giải PHương trình :)) Mấy câu còn lại tương tự
4; \(\frac{5}{x-2}+\frac{2}{x+4}=\frac{3x}{x^2+2x-8}.\)
\(\Leftrightarrow\frac{5\left(x+4\right)}{\left(x-2\right)\left(x+4\right)}+\frac{2\left(x-2\right)}{\left(x-2\right)\left(x+4\right)}=\frac{3x}{\left(x-2\right)\left(x+4\right)}\)
\(\Leftrightarrow5x+20+2x-4=3x\)
\(\Leftrightarrow4x=-16\Leftrightarrow x=-2\left(TM\right)\)
KL ::
\(5;\frac{4}{x+6}+\frac{1}{x-3}=\frac{9}{x^2+3x-18}\)
\(\Leftrightarrow\frac{4\left(x-3\right)}{\left(x+6\right)\left(x-3\right)}+\frac{x+6}{\left(x-3\right)\left(x+6\right)}=\frac{9}{\left(x-3\right)\left(x+6\right)}\)
\(\Leftrightarrow4x+x=3+9-6\)
\(\Leftrightarrow5x=6\Leftrightarrow x=\frac{6}{5}\)
1/ \(\dfrac{x+4}{4}+\dfrac{3x-7}{5}=\dfrac{7x+2}{20}\)
2/ \(\dfrac{x}{6}+\dfrac{1-3x}{9}=\dfrac{-x+1}{12}\)
3/ \(\dfrac{x-3}{3}-\dfrac{x+2}{12}=\dfrac{2x-1}{4}\)
4/ \(\dfrac{x-2}{4}-\dfrac{2x+3}{3}=\dfrac{x+6}{12}\)
5/ \(\dfrac{2x-1}{12}-\dfrac{3-x}{18}=\dfrac{-1}{36}\)
1: Ta có: \(\dfrac{x+4}{4}+\dfrac{3x-7}{5}=\dfrac{7x+2}{20}\)
\(\Leftrightarrow5x+20+12x-28=7x+2\)
\(\Leftrightarrow17x-7x=2+8=10\)
hay x=1
2: Ta có: \(\dfrac{x}{6}+\dfrac{1-3x}{9}=\dfrac{-x+1}{12}\)
\(\Leftrightarrow\dfrac{6x}{36}+\dfrac{4\left(1-3x\right)}{36}=\dfrac{3\left(-x+1\right)}{36}\)
\(\Leftrightarrow6x+4-12x=-3x+3\)
\(\Leftrightarrow-6x+3x=3-4\)
hay \(x=\dfrac{1}{3}\)
3: Ta có: \(\dfrac{x-3}{3}-\dfrac{x+2}{12}=\dfrac{2x-1}{4}\)
\(\Leftrightarrow4x-12-x-2=6x-3\)
\(\Leftrightarrow3x-14-6x+3=0\)
\(\Leftrightarrow-3x=11\)
hay \(x=-\dfrac{11}{3}\)
4: Ta có: \(\dfrac{x-2}{4}-\dfrac{2x+3}{3}=\dfrac{x+6}{12}\)
\(\Leftrightarrow3x-6-8x-12=x+6\)
\(\Leftrightarrow-5x-x=6+18\)
hay x=-4
5: Ta có: \(\dfrac{2x-1}{12}-\dfrac{3-x}{18}=\dfrac{-1}{36}\)
\(\Leftrightarrow6x-3+2x-6=-1\)
\(\Leftrightarrow8x=8\)
hay x=1
Tìm x:
1. 3x (2x + 3) - (2x + 5).(3x - 2) = 8
2. 4x (x -1) - 3(x2 - 5) -x2 = (x - 3) - (x + 4)
3. 2 (3x -1) (2x +5) - 6 (2x - 1) (x + 2) = -6
4. 3 ( 2x - 1) (3x - 1) - (2x - 3) (9x - 1) - 3 = -3
5. (3x - 1) (2x + 7) - ( x + 1) (6x - 5) = (x + 2) - (x - 5)
6. 3xy (x + y) - (x + y) (x2 + y2 + 2xy) + y3 = 27
7. 3x (8x - 4) - 6x (4x - 3) = 30
8. 3x (5 - 2x) + 2x (3x - 5) = 20
HELP ME T^T
Tìm x:
1. 3x (2x + 3) - (2x + 5).(3x - 2) = 8
\(\Leftrightarrow6x^2+9x-6x^2+4x-15x+10=0 \)
\(\Leftrightarrow-2x+10=0\Leftrightarrow x=5\)
Vậy x = 5
2. 4x (x -1) - 3(x2 - 5) -x2 = (x - 3) - (x + 4)
\(\Leftrightarrow4x^2-4x-3x^2+15-x^2=x-3-x-4\)
\(\Leftrightarrow-4x+15=-7\)
\(\Leftrightarrow-4x=-22\Leftrightarrow x=\frac{11}{2}\)
Vậy x = \(\frac{11}{2}\)
3. 2 (3x -1) (2x +5) - 6 (2x - 1) (x + 2) = -6
\(\Leftrightarrow2\left(6x^2+15x-2x-5\right)-6\left(2x^2+4x-x-2\right)=-6\)
\(\Leftrightarrow12x^2+30x-4x-10-12x^2-24x+6x+12=-6\)
\(\Leftrightarrow8x=-8\Leftrightarrow x=-1\)
Vậy x = -1
4. 3 ( 2x - 1) (3x - 1) - (2x - 3) (9x - 1) - 3 = -3
\(\Leftrightarrow3\left(6x^2-2x-3x+1\right)-18x^2+2x+27x-3-3=-3\)
\(\Leftrightarrow18x^2-6x-9x+3-18x^2+2x+27x-6=-3\)
\(\Leftrightarrow14x=0\Leftrightarrow x=0\)
Vậy x = 0
5. (3x - 1) (2x + 7) - ( x + 1) (6x - 5) = (x + 2) - (x - 5)
\(\Leftrightarrow6x^2+21x-2x-7-6x^2+5x-6x+5=7\)
\(\Leftrightarrow18x=9\Leftrightarrow x=\frac{1}{2}\)
Vậy x = \(\frac{1}{2}\)
6. 3xy (x + y) - (x + y) (x2 + y2 + 2xy) + y3 = 27
\(\Leftrightarrow3x^2y+3xy^2-\left(x+y\right)^3+y^3=27\)
\(\Leftrightarrow3x^2y+3xy^2-x^3-y^3-3x^2y-3xy^2+y^3=27\)
\(\Leftrightarrow-x^3=27\)
\(\Leftrightarrow x=-3\)
Vậy x = -3
7. 3x (8x - 4) - 6x (4x - 3) = 30
\(\Leftrightarrow24x^2-12x-24x^2+12x=30\)
\(\Leftrightarrow0=30\) ( vô lý)
Vậy pt vô nghiệm
8. 3x (5 - 2x) + 2x (3x - 5) = 20
\(\Leftrightarrow15x-6x^2+6x^2-10x=20\)
\(\Leftrightarrow5x=20\Leftrightarrow x=4\)
Vậy x = 4
giải phương trình theo phương pháp đặt ẩn phụ
a) (X+1)^2 x (2X+1)(2X+3)-18
b) (3X-2)^2(6X-5)(6X-3)-5
c) (4X+1)(12X-1)(3X+2)(x+1)-4
d) (6X+5)^2(3X+2)(x+1)-35
e) (2X-1)(X-1)(4X+3)(8X-6)-4
a) (X+1)^2 x (2X+1)(2X+3)-18
=4/4x(x+1)^2 x(2X+1)(2X+3)-18
=1/4 x (2X +2)^2 x (2X+1)(2X+3)-18
đặt y= 2X+2
....còn nữa mà mình ko biết các bạn giúp minh với
các bài còn lại làm tương tự, các bạn giúp mình với
giúp mình bài ni với :3x^2(x+1)-5x(x+1)^2+4(x+1)