a) |x-1|-2x=5
b)|9-7x|=5x-3
c)5x+2=625
d)(2x-3)2=36
a) |x-1|-2x=5
b)|9-7x|=5x-3
c)5x+2=625
d)(2x-3)2=36
a) |x-1|-2x=5
\(\Leftrightarrow\) x - 1 - 2x = 5 (đk: x\(\ge\)1 ) (1)
hoặc -x + 1 - 2x = 5 ( đk: x < 1) (2)
(1): \(\Leftrightarrow\) x - 2x = 5 + 1
\(\Leftrightarrow\) - x = 6
\(\Leftrightarrow\) x = -6 (ko thỏa mãn)
(2): \(\Leftrightarrow\) -x + 1 - 2x = 5
\(\Leftrightarrow\) -3x = 4
\(\Leftrightarrow\) x = \(\frac{-4}{3}\) (thỏa mãn)
Vậy: x = \(\frac{-4}{3}\)
b) |9-7x|=5x-3
\(\Leftrightarrow\) 9 - 7x = 5x - 3 (đk: \(\le\) \(\frac{9}{7}\) ) (1)
hoặc -9 + 7x = 5x - 3 (đk: x > \(\frac{9}{7}\) ) (2)
(1): \(\Leftrightarrow\) -7x-5x = -3-9 \(\Leftrightarrow\) -12x = -12 \(\Leftrightarrow\) x = 1 ( thỏa mãn)
(2): \(\Leftrightarrow\) 7x - 5x = -3 + 9 \(\Leftrightarrow\) 2x = 6 \(\Leftrightarrow\) x = 3 ( thỏa mãn)
Vậy: x= 1; 3
c) 5x+2 = 625
\(\Leftrightarrow\) 5x . 52 = 54
\(\Leftrightarrow\) 5x = \(\frac{5^4}{5^2}\)= 52
\(\Leftrightarrow\) x = 2
d) (2x - 3)2 = 36
\(\Leftrightarrow\) \(\left[{}\begin{matrix}2x-3=6\left(đk:x\ge\frac{3}{2}\right)\text{}\Leftrightarrow x=4,5\left(TMĐK\right)\\2x-3=-6\left(đk:x< \frac{3}{2}\right)\Leftrightarrow x=-1,5\left(TMĐK\right)\end{matrix}\right.\)
Vậy: x = 4,5; -1,5
Rút gọn :
1. (2x-5)(3x+1)-(x-3)^2+(2x+5)^2-(3x+1)^3
2. (2x-1)(2x+1)-3x-2)(2x+3)-(x-1)^3+(2x+3)^3
3. (x-2)(x^2+2x+4)-(3x-2)^3+(3x-4)^2
4. (7x-1)(8x+2)-(2x-7)^2-(x-4)^3-(3x+1)^3
5. (5x-1)(5x+1)-(x+3)(x^2-3x+9)-(2x+4)^2-(3x-4)^2+(2x-5)^3
6. (4x-1)(x+2)-(2x+5)^2-(3x-7)^2+(2x+3)^3=(3x-1)^3
1: \(=6x^2+2x-15x-5-x^2+6x-9+4x^2+20x+25-27x^3-27x^2-9x-1\)
=-27x^3-18x^2+4x+10
2: =4x^2-1-6x^2-9x+4x+6-x^3+3x^2-3x+1+8x^3+36x^2+54x+27
=7x^3+37x^2+46x+33
5:
\(=25x^2-1-x^3-27-4x^2-16x-16-9x^2+24x-16+\left(2x-5\right)^3\)
\(=8x^3-60x^2+150-125+12x^2-x^3+8x-60\)
=7x^3-48x^2+8x-35
tìm A. a) A(x-5)/x^2-4x-5=3x^2+9x/x^2+4x+3
b) x^2+x-6/A(x+3)=(5x-1)(x-2)/5x^3-x^2+15x-3
c)x^2-25/2x^2+7x-15=(x-5)A/2x^2+x-6
mong mọi ng làm giúp ạ
b: \(\Leftrightarrow\dfrac{x-2}{A}=\dfrac{\left(5x-1\right)\left(x-2\right)}{x^2\left(5x-1\right)+3\left(5x-1\right)}=\dfrac{x-2}{x^2+3}\)
hay \(A=x^2+3\)
a) 5x + 2x = 62 - 50
b) 5x + x = 150 : 2 + 3
c) 6x + x = 511 : 59 + 31
d) 5x + 3x = 36 : 33.4 + 12
4x + 2x = 68 – 219 : 216
https://hoc24.vn/cau-hoi/a-5x-2x-62-50b-5x-x-150-2-3c-6x-x-511-59-31d-5x-3x-36-334-124x-2x-68-219-216.2785429565572
a: \(\Leftrightarrow7x=35\)
hay x=5
b: \(\Leftrightarrow6x=78\)
hay x=13
Các bạn giúp mình nha !!! Thanks các bạn !!!
a) 6xz-7x²/4y²+9xz+7x²/4y²
b) 5x+10/4x-8:2x+4/4-2x
c) (2/2x-1 - 2/1-2x):4x²/4x²-1
d) 5b/b²-9.b-3/10b
e) (5/3(x+2)² - 2x/3x+6 + 1/3).x+2/x-3
f) (x/x-y - y/x+y + 2xy/x²-y²):x+y/2x-2y.
Giải phương trình sau :
a,\(\dfrac{7-3x}{12}+\dfrac{5x+2}{7}=x+13\)
b,\(\dfrac{3\left(x+3\right)}{4}-\dfrac{1}{2}=\dfrac{5x+9}{7}-\dfrac{7x-9}{4}\)
c,\(\dfrac{2x+1}{3}-\dfrac{5x+2}{7}=x+3\)
d,\(\dfrac{2x-3}{3}-\dfrac{2x+3}{7}=\dfrac{4x+3}{5}-17\)
a: \(\Leftrightarrow7\left(7-3x\right)+12\left(5x+2\right)=84\left(x+13\right)\)
\(\Leftrightarrow49-21x+60x+24=84x+1092\)
\(\Leftrightarrow39x-84x=1092-73\)
=>-45x=1019
hay x=-1019/45
b: \(\Leftrightarrow21\left(x+3\right)-14=4\left(5x+9\right)-7\left(7x-9\right)\)
=>21x+63-14=20x+36-49x+63
=>21x+49=-29x+99
=>50x=50
hay x=1
c: \(\Leftrightarrow7\left(2x+1\right)-3\left(5x+2\right)=21x+63\)
=>14x+7-15x-6-21x-63=0
=>-22x-64=0
hay x=-32/11
d: \(\Leftrightarrow35\left(2x-3\right)-15\left(2x+3\right)=21\left(4x+3\right)-17\cdot105\)
=>70x-105-30x-45=84x+63-1785
=>40x-150-84x+1722=0
=>-44x+1572=0
hay x=393/11
a, msc 12.7=84
Chuyển vế về =0 rồi làm
b,msc 28
c,làm tương tự
a, \(\Rightarrow49-21x+60x+24=84x+1092\)
\(\Leftrightarrow-45x=1019\Leftrightarrow x=-\dfrac{1019}{45}\)
b, \(\Rightarrow21\left(x+3\right)-14=4\left(5x+9\right)-7\left(7x-9\right)\)
\(\Leftrightarrow21x+63-14=20x+36-49x+63\)
\(\Leftrightarrow50x=50\Leftrightarrow x=1\)
c, \(\Rightarrow14x+7-15x-6=21x+63\Leftrightarrow-22x=62\Leftrightarrow x=-\dfrac{31}{11}\)
d, \(\Rightarrow35\left(2x-3\right)-15\left(2x+3\right)=21\left(4x+3\right)-105.17\)
\(\Leftrightarrow70x-105-30x-45=84x+63-1785\)
\(\Leftrightarrow-44x=-1572\Leftrightarrow x=\dfrac{393}{11}\)
Viết phương trình đường thẳng (d) đi qua hai điểm A (-2;1) và M. Biết M nằm trên đường thẳng (d') y= 3-2x và M có hoành độ bằng \(\dfrac{1}{2}\)?
A. y = 2x+5
B. y = -2x-3
C. y = \(\dfrac{2}{5}x\)+\(\dfrac{9}{5}\)
D. y = 5x-3
Mình đang cần rất gấp ạ! Cảm ơn mn nhiều.
Thực hiện phép tính
a, (2x^3-4x+5x):(-3/2x)
b, (4x^3-5x+x):(2x-1)
c, (-3x^4+5x^3+6x^2-7x+1):(x^2+3x-1)
đ, (3^3-5x+2):(x-3)
a: \(=2x^3:\dfrac{-3}{2}x+4x:\dfrac{3}{2}x-5:\dfrac{3}{2}\)
=-4/3x^2+8/3-10/3
=-4/3x^2-2/3
d: \(\dfrac{3x^3-5x+2}{x-3}=\dfrac{3x^3-9x^2+9x^2-27x+22x-66+68}{x-3}\)
\(=3x^2+9x+22+\dfrac{68}{x-3}\)
1.Tính
a, 5x^3yz . (-7x^2y^3)
b, 6x(x-5) -x(6x+3)
c, (x-9)(x^2-2x-1)
2.Cho A (x)=10-2x+4x^3-5x^2
B(x)=-10x^3-5x+6x^2-20
Tính A(x)+B(x); A(x)-B(x)
3.Tìm nghiệm
a,M(x)= 5x+20
b,N(x)=100x^2-49
c,P(x)=3x-15
b. 6x(x - 5) - x(6x + 3)
= x(6x - 30) - x(6x + 3)
= x(6x - 30 - 6x - 3)
= x(-33)
= -33x