\(X^2=49\\ Mà:7^2=49;\left(-7\right)^2=49\\ \Rightarrow X=7.hoặc.x=-7\\ ----\\ b,\left(5x+1\right)^2=121=11^2=\left(-11\right)^2\\ Nên:5x+1=11.hoặc.5x+1=-11\\ Nên:5x=10.hoặc.5x=-12\\ Vậy:x=2.hoặc.x=-\dfrac{12}{5}\\ ---\\ 3x+36=-7x-64\\ \Rightarrow3x+7x=-64-36\\ \Rightarrow10x=-100\\ \Rightarrow x=-\dfrac{100}{10}=-10\\ ---\\ -5x-1178=14x+145\\ \Rightarrow14x+5x=-1178-145\\ \Rightarrow19x=-1323\\ \Rightarrow x=\dfrac{-1323}{19}\)

\(a,\Rightarrow\left[{}\begin{matrix}5x+1=\dfrac{6}{7}\\5x+1=-\dfrac{6}{7}\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}5x=\dfrac{1}{7}\\5x=-\dfrac{13}{7}\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=\dfrac{1}{35}\\x=-\dfrac{13}{35}\end{matrix}\right.\\ b,\Rightarrow\left(-\dfrac{1}{8}\right)^x=\dfrac{1}{64}=\left(-\dfrac{1}{8}\right)^2\Rightarrow x=2\\ c,\Rightarrow\left(x-2\right)\left(2x+3\right)=0\\ \Rightarrow\left[{}\begin{matrix}x=2\\x=-\dfrac{3}{2}\end{matrix}\right.\\ d,\Rightarrow\left(x+1\right)^{x+10}-\left(x+1\right)^{x+4}=0\\ \Rightarrow\left(x+1\right)^{x+4}\left[\left(x+1\right)^6-1\right]=0\\ \Rightarrow\left[{}\begin{matrix}x+1=0\\\left(x+1\right)^6=1\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x+1=0\\x+1=1\\x+1=-1\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=-1\\x=0\\x=-2\end{matrix}\right.\\ e,\Rightarrow\dfrac{3}{4}\sqrt{x}=\dfrac{5}{6}\left(x\ge0\right)\\ \Rightarrow\sqrt{x}=\dfrac{10}{9}\Rightarrow x=\dfrac{100}{81}\)

Bạn ghi đề lại câu a.

`a)5x(x-1)-(x+2)(5x-7)=6`

`<=>5x^2-5x-(5x^2-7x+10x-14)=6`

`<=>5x^2-5x-(5x^2+3x-14)=6`

`<=>-8x+14=6`

`<=>8x=8<=>x=1`

Vậy `x=1`

`b)(x+2)^2-(x^2-4)=0`

`<=>x^2+4x+4-x^2+4=0`

`<=>4x+8=0`

`<=>4x=-8`

`<=>x=-2`

Vậy `x=-2`

a)x=5/2

b)x=-2

a)5x.(x-1)-(x+2).(5x-7)=6

<=> 5x²-5x-(5x²-7x+10x-14)=6

<=>  5x²-5x-5x²+7x-10x+14=6

<=> -8x+14=6

<=> -8x=-8 => x=1

Vậy x=1

b) (x+2)²-(x²-4)=0

<=> (x+2)²-(x²-2²)=0 <=> (x+2)²-(x-2)(x+2)=0

<=> (x+2)[(x+2)-(x-2)]=0

<=> (x+2)(x+2-x+2)=0

<=> (x+2).4=0

=> x+2=0

=> x=-2

Vậy x=-2

\(\left(5x+1\right)^2=\frac{36}{49}\)

\(\left(5x+1\right)^2=\left(\frac{6}{9}\right)^2\)

\(5x+1=\frac{6}{9}\)

\(5x=\frac{6}{9}-1\)

\(x=\frac{-1}{3}:5=\frac{-1}{3}.\frac{1}{5}=\frac{-1}{15}\)

  \(\left(5x+1\right)^2=\frac{36}{49}\)

(+) TH 1: 5x + 1 = 6/7

              5x        = 6/7 - 1

               5x        =  -1/7

                 x        = -1/7 : 5 

                 x          = -1 /35

(+) TH2 : 5x + 1 = - 6/7

             5x         = -6/7 - 1

             5x         = -13/7

               x         =-13/7 : 5 

               x          = -13/35

( 5x + 1 )² = 36/49

<=> ( 5x + 1 )² = ( ±6/7 )²

<=> 5x + 1 = 6/7 hoặc 5x + 1 = -6/7

<=> x = -1/35 hoặc x = -13/35

\(\left(5x+1\right)^2=\frac{36}{49}\)

\(\Rightarrow\orbr{\begin{cases}5x+1=\frac{6}{7}\\5x+1=\frac{-6}{7}\end{cases}}\)\(\)

\(\Rightarrow\orbr{\begin{cases}5x=\frac{-1}{7}\\5x=\frac{-13}{7}\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x=\frac{-1}{35}\\x=\frac{-13}{35}\end{cases}}\)

\(\left(5x+1\right)=\pm\sqrt{\frac{36}{49}}=\pm\frac{6}{7}\)                         

\(\orbr{\begin{cases}5x+1=\frac{6}{7}\\5x+1=-\frac{6}{7}\end{cases}}\)      

\(\orbr{\begin{cases}5x=\frac{-1}{7}\\5x=\frac{-13}{7}\end{cases}}\)    

\(\orbr{\begin{cases}x=\frac{-1}{35}\\x=\frac{-13}{35}\end{cases}}\)

a) \(\Rightarrow\left(x-1\right)^2=25\)

\(\Rightarrow\left[{}\begin{matrix}x-1=5\\x-1=-5\end{matrix}\right.\)\(\Rightarrow\left[{}\begin{matrix}x=6\\x=-4\end{matrix}\right.\)

b) \(\Rightarrow25x^2+10x+1-25x^2+9=30\)

\(\Rightarrow10x=20\Rightarrow x=2\)

a. x² - 2x + 1 = 25

<=> x² - 2x - 24 = 0

<=> x² - 6x + 4x - 24 = 0

<=> x(x - 6) + 4(x - 6) = 0

<=> (x + 4)(x - 6) = 0

<=> \(\left[{}\begin{matrix}x+4=0\\x-6=0\end{matrix}\right.\)

<=> \(\left[{}\begin{matrix}x=-4\\x=6\end{matrix}\right.\)

b. (5x + 1)² - (5x - 3)(5x + 3) = 30

<=> 25x² + 10x + 1 - 25x² + 9 = 30

<=> 25x² - 25x² + 10x = 30 - 1 - 9

<=> 10x = 20

<=> x = 2

a) Ta có: \(x^2-2x+1=25\)

\(\Leftrightarrow\left(x-1\right)^2=25\)

\(\Leftrightarrow\left[{}\begin{matrix}x-1=5\\x-1=-5\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=6\\x=-4\end{matrix}\right.\)

b) Ta có: \(\left(5x+1\right)^2-\left(5x-3\right)\left(5x+3\right)=30\)

\(\Leftrightarrow25x^2+10x+1-25x^2+9=30\)

\(\Leftrightarrow10x=20\)

hay x=2

c) Ta có: \(\left(x-1\right)\left(x^2+x+1\right)-x\left(x+2\right)\left(x-2\right)=5\)

\(\Leftrightarrow x^3-1-x\left(x^2-4\right)=5\)

\(\Leftrightarrow x^3-1-x^3+4x=5\)

\(\Leftrightarrow4x=6\)

hay \(x=\dfrac{3}{2}\)

d) Ta có: \(\left(x-2\right)^3-\left(x-3\right)\left(x^2+3x+9\right)+6\left(x+1\right)^2=15\)

\(\Leftrightarrow x^3-6x^2+12x-8-x^3+27+6\left(x^2+2x+1\right)=15\)

\(\Leftrightarrow-6x^2+12x+19+6x^2+12x+6=15\)

\(\Leftrightarrow24x=-10\)

hay \(x=-\dfrac{5}{12}\)

a,\(< =>\left(x-1\right)^2-5^2=0< =>\left(x-1-5\right)\left(x-1+5\right)=0\)

\(< =>\left(x-6\right)\left(x+4\right)=0=>\left[{}\begin{matrix}x=6\\x=-4\end{matrix}\right.\)

b,\(< =>25x^2+10x+1-25x^2+9-30=0\)

\(< =>10x-20=0< =>10\left(x-2\right)=0< =>x=2\)

c,\(< =>x^3-1-x\left(x^2-4\right)-5=0\)

\(< =>x^3-1-x^2+4x-5=0< =>4x-6=0< =>x=\dfrac{6}{4}\)\(d,< =>\left(x-2\right)^3-x^3+3^3+6x^2+12x+6-15=0\)

\(< =>x^3-6x^2+12x-x^3+6x^2+12x+10=0\)

\(< =>24x+10=0< =>x=-\dfrac{5}{12}\)

a: Ta có: \(x^2-2x+1=25\)

\(\Leftrightarrow\left(x-4\right)\left(x-6\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=4\\x=6\end{matrix}\right.\)

b: Ta có: \(\left(5x+1\right)^2-\left(5x-3\right)\left(5x+3\right)=30\)

\(\Leftrightarrow25x^2+10x+1-25x^2+9=30\)

\(\Leftrightarrow10x=20\)

hay x=2

c: Ta có: \(\left(x-1\right)\left(x^2+x+1\right)-x\left(x+2\right)\left(x-2\right)=5\)

\(\Leftrightarrow x^3-1-x\left(x^2-4\right)=5\)

\(\Leftrightarrow x^3-1-x^3+4x=5\)

\(\Leftrightarrow4x=6\)

hay \(x=\dfrac{3}{2}\)