Question

bài 1:tìm x

(x+1).(x-1)=(x+2).(x+5)

giúp mk vs ạ

Answer 1

(x+1).(x-1)=(x+2).(x+5)

=> x^2-1=x^2+5x+2x+10

<=> x^2-x^2-5x-2x-1-10=0

<=> -7x-11=0

<=> -7x=11

<=> x=-11/7

Answer 2

\(\left(x+1\right)\left(x-1\right)=\left(x+2\right)\left(x+5\right)\\ x^2-x+x-1=x^2+5x+2x+10\\ x^2-1=x^2+10x+10\\ x^2-x^2=1+10+10x\\ 10x+11=0\\ 10x=-11\\ x=\frac{-11}{10}\)

Vậy \(x=\frac{-11}{10}\)