Tìm x biết 1/x^2+3x + 1/(x^2+9x+18) +1/(x^2+15x+54) +1/3x+27 +1/673=0
Những câu hỏi liên quan
\(\frac{1}{x^2+3x}+\frac{1}{x^2+9x+18}+\frac{1}{x^2+15x+54}=\frac{29}{27}\)
giải phương trình :
\(\frac{1}{x^2+3x}+\frac{1}{x^2+9x+18}+\frac{1}{x^2+15x+54}=\frac{1}{3}\left(27-\frac{1}{x+9}\right)\)
giúp mính vs nha mấy bạn huhu mai mik phải nộp r
\(\frac{1}{x^2+3}+\frac{1}{x^2+9x+18}+\frac{1}{x^2+15x+54}=\frac{1}{2}\left(27-\frac{1}{x+9}\right)\)
\(\Leftrightarrow\frac{3}{x\left(x+3\right)}+\frac{3}{\left(x+3\right)\left(x+6\right)}+\frac{3}{\left(x+6\right)\left(x+9\right)}=27-\frac{1}{x+9}\)
Mà
\(\frac{3}{x\left(x+3\right)}+\frac{3}{\left(x+3\right)\left(x+6\right)}+\frac{3}{\left(x+6\right)\left(x+9\right)}\)
\(=\frac{1}{x}-\frac{1}{x+3}+\frac{1}{x+3}-\frac{1}{x+6}+\frac{1}{x+6}-\frac{1}{x+9}\)
\(=\frac{1}{x}-\frac{1}{x+9}\)
\(\Rightarrow\frac{1}{x}=27\Rightarrow x=\frac{1}{27}\)
Thực hiện phép trừ \(\dfrac{1}{x-3}-\dfrac{1}{x}\) rồi áp dụng tính nhanh vào biểu thức:
\(B=\dfrac{1}{x^2-3x}+\dfrac{1}{x^2-9x+18}+\dfrac{1}{x^2-15x+54}+\dfrac{1}{x^2-21x+108}\)
\(\dfrac{1}{x-3}-\dfrac{1}{x}=\dfrac{x-\left(x-3\right)}{x\left(x-3\right)}=\dfrac{x-x+3}{x\left(x-3\right)}=\dfrac{3}{x\left(x-3\right)}\)
\(B=\dfrac{1}{x^2-3x}+\dfrac{1}{x^2-9x+18}+\dfrac{1}{x^2-15x+54}+\dfrac{1}{x^2-21x+108}\)
\(=\dfrac{1}{x\left(x-3\right)}+\dfrac{1}{\left(x-3\right)\left(x-6\right)}+\dfrac{1}{\left(x-6\right)\left(x-9\right)}+\dfrac{1}{\left(x-9\right)\left(x-12\right)}\)
\(=\dfrac{1}{3}\left(\dfrac{3}{x\left(x-3\right)}+\dfrac{3}{\left(x-3\right)\left(x-6\right)}+\dfrac{3}{\left(x-6\right)\left(x-9\right)}+\dfrac{3}{\left(x-9\right)\left(x-12\right)}\right)\)
\(=\dfrac{1}{3}\left(-\dfrac{1}{x}+\dfrac{1}{x-3}-\dfrac{1}{x-3}+\dfrac{1}{x-6}-\dfrac{1}{x-6}+\dfrac{1}{x-9}-\dfrac{1}{x-9}+\dfrac{1}{x-12}\right)\)
\(=\dfrac{1}{3}\left(-\dfrac{1}{x}+\dfrac{1}{x-12}\right)\)
\(=\dfrac{1}{3}\cdot\dfrac{-\left(x-12\right)+x}{x\left(x-12\right)}\)
\(=\dfrac{4}{x\left(x-12\right)}\)
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giúp minh vs:
1/(x(x+3))+1/((x+3)(x+6))+1/(x^2+15x+54)+1/(3x+27)
1) (4-3x) (10x-5)02) (7-2x) (4+8x) 03) (9-7x) (11-3x) 04) (7-14x) (x-2) 05) (2x+1) (x-3) 06) (8-3x) (-3x+5) 07) (16-8x) (2-6x) 08) (x+4) (6x-12) 09) (11-33x) (x+11) 010) (x-1/4) (x+5/6) 011) (7/8-2x) (3x+1/3) 012) 3x - 2x^2 013) 5x + 10x^2 014) 4x + 3x^2 015) -8x^2 + x 016) 10x^2 - 15x 017) x^2 -4 018) 9 - x^2 019) x^2 -1 020) (x-3) (2x-1) (2x-1) ( 2x+3)21) (5+4x) (-x+2) (5+4x) (7+5x)22) (4+x) (x-5) (3x-8) (x-5) 0 23) (3x-8) (7-21x) - (9+2x) (7-21x)24) (10+ 7x) (x+1) (9x-2)(...
Đọc tiếp
1) (4-3x) (10x-5)=0
2) (7-2x) (4+8x) = 0
3) (9-7x) (11-3x) = 0
4) (7-14x) (x-2) = 0
5) (2x+1) (x-3) = 0
6) (8-3x) (-3x+5) = 0
7) (16-8x) (2-6x) = 0
8) (x+4) (6x-12) = 0
9) (11-33x) (x+11) = 0
10) (x-1/4) (x+5/6) = 0
11) (7/8-2x) (3x+1/3) = 0
12) 3x - 2x^2 = 0
13) 5x + 10x^2 = 0
14) 4x + 3x^2 = 0
15) -8x^2 + x =0
16) 10x^2 - 15x = 0
17) x^2 -4 =0
18) 9 - x^2 = 0
19) x^2 -1 = 0
20) (x-3) (2x-1) = (2x-1) ( 2x+3)
21) (5+4x) (-x+2) = (5+4x) (7+5x)
22) (4+x) (x-5) = (3x-8) (x-5) = 0
23) (3x-8) (7-21x) - (9+2x) (7-21x)
24) (10+ 7x) (x+1) = (9x-2)(x-1)
25) (9x-4) (x-1/2) - (x-1/2) (6+x) = 0
26) 9x^2 - 1 = (3x-1) (x+4)
27) (x+7) (3x+1) = 49-x^2
28) (2x+1)^2 = (x-1)^2
29)x^3- 5x^2+6x = 0
30) 3x^2 + 5x + 2 = 0
Giảii giúpp mìnhh đyy mọii ngườii .
\(\left(4-3x\right)\left(10x-5\right)=0\)
\(\Rightarrow\orbr{\begin{cases}4-3x=0\\10x-5=0\end{cases}\Rightarrow\orbr{\begin{cases}3x=4\\10x=5\end{cases}\Rightarrow}\orbr{\begin{cases}x=\frac{4}{3}\\x=\frac{1}{2}\end{cases}}}\)
\(\left(7-2x\right)\left(4+8x\right)=0\)
\(\Rightarrow\orbr{\begin{cases}7-2x=0\\4+8x=0\end{cases}\Rightarrow\orbr{\begin{cases}2x=7\\8x=-4\end{cases}\Rightarrow\orbr{\begin{cases}x=\frac{7}{2}\\x=-\frac{1}{2}\end{cases}}}}\)
rồi thực hiện đến hết ...
Brainchild bé ngây thơ qus e , ko thực hiện đến hết như thế đc đâu :>
\(\left(x-3\right)\left(2x-1\right)=\left(2x-1\right)\left(2x+3\right)\)
\(2x^2-7x+3=4x^2+4x-3\)
\(2x^2-7x+3-4x^2-4x+3=0\)
\(-2x^2-11x+6=0\)
\(2x^2+11x-6=0\)
\(2x^2+12x-x-6=0\)
\(2x\left(x+6\right)-\left(x+6\right)=0\)
\(\left(x+6\right)\left(2x-1\right)=0\)
\(x+6=0\Leftrightarrow x=-6\)
\(2x-1=0\Leftrightarrow2x=1\Leftrightarrow x=\frac{1}{2}\)
\(3x-2x^2=0\)
\(x\left(2x-3\right)=0\)
\(x=0\)
\(2x-3=0\Leftrightarrow2x=3\Leftrightarrow x=\frac{3}{2}\)
Tự lm tiếp nha
tìm x
a(2x+1)(x-4)=(2x+1)^2
b(x-4)(x^2+4x-16)-(x^2-6)=2
c( 2x-1)^2-(3x+4)^2=0
d(9x+2)(x-1)-(3x-1)^2=0
e(2x+3)^2-4(x-1)(x-1)(x+1)=0
f)15x(x+4-6x-24=0
g)(4-10x)(2-3x)-30^2=0
giải giùm mik nha các bn :3
bạn đăng tách ra nhé
a, \(\left(2x+1\right)\left(x-4\right)=\left(2x+1\right)^2\)
\(\Leftrightarrow2x^2-7x-4=4x^2+4x+1\Leftrightarrow2x^2+11x+5=0\)
\(\Leftrightarrow\left(x+5\right)\left(2x+1\right)=0\Leftrightarrow x=-5;x=-\frac{1}{2}\)
b, sửa đề : \(\left(x-4\right)\left(x^2+4x+16\right)-\left(x^2-6\right)=2\)
\(\Leftrightarrow x^3-64-x^2+6=2\Leftrightarrow x^3-x^2-60=0\Leftrightarrow x=4,27...\)
c, \(\left(2x-1\right)^2-\left(3x+4\right)^2=0\Leftrightarrow\left(2x-1+3x+4\right)\left(2x-1-3x-4\right)=0\)
\(\Leftrightarrow\left(5x+3\right)\left(-x-5\right)=0\Leftrightarrow x=-\frac{3}{5};x=-5\)
d, \(\left(9x+2\right)\left(x-1\right)-\left(3x-1\right)^2=0\)
\(\Leftrightarrow9x^2-7x-2-9x^2+6x-1=0\Leftrightarrow-x-3=0\Leftrightarrow x=-3\)
e, \(\left(2x+3\right)^2-4\left(x-1\right)\left(x-1\right)\left(x+1\right)=0\)
\(\Leftrightarrow4x^2+12x+9-4\left(x-1\right)\left(x^2-1\right)=0\)
\(\Leftrightarrow4x^2+12x+9-4\left(x^3-x-x^2+1\right)=0\)
\(\Leftrightarrow4x^2+12x+9-4x^3+4x+4x^2-4=0\)
\(\Leftrightarrow-4x^3+8x^2+16x+5=0\Leftrightarrow x=-0,9...;x=-0,41...;x=3,31...\)
f, \(15x\left(x+4-6x-24\right)=0\Leftrightarrow15\left(-5x-20\right)=0\)
\(\Leftrightarrow-75x-300=0\Leftrightarrow x=-4\)
g, \(\left(4x-10\right)\left(2-3x\right)-30^2=0\)
\(\Leftrightarrow8x-12x^2-20+30x-900=0\Leftrightarrow-12x^2+38x-920=0\)
vô nghiệm
Giair pt:
c, x ( 3x-1) (3x+1) (3x+2) =8
d, (x+1) (2x+3) (2x+5) (x+3)=45
e,x4+ 3x3 - 15x2 - 19x + 3 = 0
f, \(\frac{1}{x^2+x}+\frac{1}{x^2+3x+2}+\frac{1}{x^2+5x+6}+\frac{1}{x^2+7x+12}=\frac{1}{3}\)
h,\(\frac{1}{x^2+9x+20}+\frac{1}{x^2+11x+30}+\frac{1}{x^2+13x+42}=\frac{1}{18}\)
Tìm x
a, (x+2)^3 - x(x^2+6x-3)=0
b,(x+4)^3 - x(x+6)^2=7
c, (x-1)^3 - x(x^2-3x-2)=0
d,1000x^3+90x(10x+3)+27=0
e,125x^3+15x(5x+1)= -1
f, 27x^3+45x(3x+5)+133=0
a, \(\left(x+2\right)^3-x\left(x^2+6x-3\right)=0\Leftrightarrow x^3+4x^2+4x+2x^2+8x+8-x^3-6x^2+3x=0\)
\(\Leftrightarrow15x+8=0\Leftrightarrow x=-\frac{8}{15}\)
b, \(\left(x+4\right)^3-x\left(x+6\right)^2=7\Leftrightarrow12x+64=0\Leftrightarrow x=-\frac{19}{4}\)làm tắt:P
Tự làm nốt nhé
Tìm x: (2.|x|-1).(7-3x)=0. ; (x^2+1).(1/2-3x)<0. ; (|x|+1).(15x-1)=0.
( 2. l x l - 1) .(7 - 3x ) =0 ( x2 + 1 ). ( 1/2 - 3x ) <0 ( l x l + 1 ) . ( 15x - 1 ) = 0
=> 2 . l x l - 1 = 0 hoặc 7 - 3x = 0 => x2+1 hoặc 1/2 -3x < 0 => l x l + 1 hoặc 15x - 1 =0
+ 2 . l x l - 1 = 0 => 2 . l x l =1 => x = 1/2 + x2 +1< 0 => x không tồn tại + l x l - 1 = 0 => l x l = 1 => thuộc 1 : -1
+ 7 - 3x = 0 => 3x = 7 => x = 7/3 + 1/2 - 3x < 0 => 3x > 1/2 => x > 1 + 15x - 1 = 0 => 15x =1 => x = 1/15
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