Question

2x\(^2\)-10x=-30

Answer 1

\(2x^2-10x=-30\)

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

\(\Leftrightarrow x^2-2\cdot x\cdot\dfrac{5}{2}+\dfrac{25}{4}+\dfrac{35}{4}=0\)

\(\Leftrightarrow\left(x-\dfrac{5}{2}\right)^2+\dfrac{35}{4}=0\)(vô lý)

Answer 2

2x²-10x=-30

=>2x²-10x+30=0

=>2x(x-5+30)=0

=>_2x=0=>x=0

    _x-5+30=0=>x+25=0=>x=-25