Question

tìm x

(x + 3)² + (x - 2)(x +2) - 2(x - 1)²=23

 

Answer 1

\(\left(x+3\right)^2+\left(x-2\right)\left(x+2\right)-2\left(x-1\right)^2=23\)

\(x^2+6x+9+x^2-4-2\left(x^2-2x+1\right)=23\)

\(x^2+6x+9+x^2-4-2x^2+4x-2=23\)

\(10x+3=23\)

\(10x=20\)

\(x=2\)

Answer 2

=>x^2+6x+9+x^2-4-2x^2+4x-2=23

=>10x+5=23

=>10x=18

=>x=1,8