Question

Tìm x,biết(x+2)(x+1)-(x-3)(x+5)=0

Answer 1

\(\left(x+2\right)\left(x+1\right)-\left(x-3\right)\left(x+5\right)=0\)

\(\Leftrightarrow x^2+x+2x+2-x^2-5x+3x+15=0\)

\(\Leftrightarrow x+17=0\)

\(\Leftrightarrow x=-17\)

Answer 2

(x+2)(x+1)-(x-3)(x+5)=0

\(\Leftrightarrow\) (x²+x+2x+2)-(x²+5x-3x-15)=0

\(\Leftrightarrow\)x²+x+2x+2-x²-5x+3x+15=0

\(\Leftrightarrow\)x+17=0

\(\Rightarrow\)x=-17