2x^2-1=49
49.(2x+1)^2:25-49=0
|2x-5|-7=(1/492)x(1/49-42)...x(1/49-1/20152)
thank các bạn nha
1 . Tìm x biết :
a . 2x - ( x + 15 - 29 ) = 17 - 11
b . 49 - ( x - 12 + 54 ) = 2x + 49
c . ( 2x - 5 ) . 2 = 49
d . 2 . | x - 3 | -1 = 6
e . 3 . | x + 1 | - 2 = 4
f . 4 x + 2 + 4 x = 1088
3.|x+1|-2=4
3.|x+1|=4+2
3.|x+1|=6
|x+1|=6:3
|x+1|=2
Trường hợp 1 x+1=2
x=2-1
x=1
trường hợp 2
x+1=-2
x=(-2)-1
x=-3
==> x thuộc {1; -3}
k mk nha chúc học tốt
Bài 1: Tìm x bt:
a) (2x + 2/7)^2 - 2/49 = -11/49
x (x-2)(x+2)-(x-3)(x^2+3x+9)
(2x+7)(4x^2-14x+49)-2x (2x-1)(2x+1)
\(x\left(x-2\right)\left(x+2\right)-\left(x-3\right)\left(x^2+3x+9\right)\)
\(=\left(x^2-2x\right)\left(x+2\right)-\left(x-3\right)\left(x^2+3x+9\right)\)
\(=x^3+2x^2-2x^2-4x-x^3-3x^2-9x+3x^2+9x+27\)
\(=9x-4x+27=5x+27\)
\(\left(2x+7\right)\left(4x^2-14x+49\right)-2x\left(2x-1\right)\left(2x+1\right)\)
\(=\left(2x+7\right)\left(4x^2-14+49\right)-\left(4x^2-2x\right)\left(2x+1\right)\)
\(8x^3-28x+98x+28x^2-98+343-8x^3-4x^2+4x^2+2x\)
\(\left(98x-28x+2x\right)+343=72x+343\)
tìm x
( 2x +5)^2 -2 (2x +5)(x-1)+ (x+1)^2=49
\(\left(2x+5\right)^2-2\left(2x+5\right)\left(x-1\right)+\left(x+1\right)^2=49\)
<=>\(\left\{\left(2x-5\right)-\left(x-1\right)\right\}^2=49\)
<=> \(\left(2x-5-x+1\right)^2=49\)
<=> \(\left(x-4\right)^2=49\)
<=> \(\hept{\begin{cases}x-4=7\\x-4=-7\end{cases}}\)
<=> \(\hept{\begin{cases}x=11\\x=-3\end{cases}}\)
học tốt
Phân tích thành nhân tử
A=(2x+7)(4x^2-14x+49)-2x(4x^2-1)
a 49 - ( 2x - 1 )^2 = 0
b x^2 - 3x = 40
c ( x^3 + x - 10 ) : ( x - 2 ) - x^2 +2x = 1
b: =>(x-8)(x+5)=0
=>x=8 hoặc x=-5
1) giải pt :
a) \(\dfrac{7x+10}{x+1}\left(x^2-x-2\right)-\dfrac{7x+10}{x+1}\left(2x^2-3x-5\right)=0\)
b) \(\dfrac{13}{2x^2+x-21}+\dfrac{1}{2x+7}+\dfrac{6}{9-x^2}=0\)
c) \(\dfrac{x-49}{50}+\dfrac{x-50}{49}=\dfrac{49}{x-50}+\dfrac{50}{x-49}\)
d) \(\dfrac{1+\dfrac{x}{x+3}}{1-\dfrac{x}{x+3}}=3\)
a: \(\Leftrightarrow\dfrac{7x+10}{x+1}\left(x^2-x-2-2x^2+3x+5\right)=0\)
\(\Leftrightarrow\left(7x+10\right)\left(-x^2+2x+3\right)=0\)
\(\Leftrightarrow\left(7x+10\right)\cdot\left(x^2-2x-3\right)=0\)
=>(7x+10)(x-3)=0
=>x=3 hoặc x=-10/7
b: \(\Leftrightarrow\dfrac{13}{\left(2x+7\right)\left(x-3\right)}+\dfrac{1}{2x+7}-\dfrac{6}{\left(x-3\right)\left(x+3\right)}=0\)
\(\Leftrightarrow13\left(x+3\right)+x^2-9-12x-42=0\)
\(\Leftrightarrow x^2-12x-51+13x+39=0\)
\(\Leftrightarrow x^2+x-12=0\)
=>(x+4)(x-3)=0
=>x=-4