Question

Tìm x :

( 36x² - 25 ) - ( 6x + 5 ) ( x + 1) = 0  

Answer 1

\(\left(36x^2-25\right)-\left(6x+5\right)\left(x+1\right)=0\)

\(\Leftrightarrow\left(6x+5\right)\left(6x-5\right)-\left(6x+5\right)\left(x+1\right)=0\)

\(\Leftrightarrow\left(6x+5\right)\left(6x-5-x-1\right)=0\)

\(\Leftrightarrow\left(6x+5\right)\left(5x-6\right)=0\)

\(\Leftrightarrow\orbr{\begin{cases}x=\frac{-5}{6}\\x=\frac{6}{5}\end{cases}}\)

Answer 2

\(\left(36x^2-25\right)-\left(6x+5\right)\left(x+1\right)=0\Leftrightarrow\left(6x-5\right)\left(6x+5\right)-\left(6x+5\right)\left(x+1\right)=0\)

\(\Leftrightarrow\left(6x+5\right)\left(5x-6\right)=0\Leftrightarrow\orbr{\begin{cases}x=\frac{-5}{6}\\x=\frac{6}{5}\end{cases}}\)

Answer 3

......

=>(6x+5)(6x-5) - (6x+5)(x+1)=0

=>(6x+5)(5x-4)=0

=>x=-5/6 và x= 4/5