Question

tìm x để -x^2+4x+2=6

Answer 1

\(-x^2+4x+2=6\Leftrightarrow x^2-4x+4=0\Leftrightarrow\left(x-2\right)^2=0\Leftrightarrow x-2=0\Leftrightarrow x=2\)

Answer 2

-x²+4x+2=6

-x²+4x+2-6=0

-x²+4x-4=0

-x²+2x+2x-4=0

-x.(x-2)+2(x-2)=0

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

-(x-2)(x-2)=0

-(x-2)²=0

=>x-2=0

=>x=2