Question

1 Thực hiện phép tính 

a) 2 . ( x^2 - x ) - 2x^2 = 3

b) 2 . ( x^2 + x ) - 2x = 8

Ai giúp mình với !!! 

Answer 1

a) \(2\left(x^2-x\right)-2x^2=3\)

\(\Leftrightarrow2x^2-2x-2x^2=3\)

\(\Leftrightarrow-2x=3\Leftrightarrow x=-\frac{3}{2}\)

b) \(2\left(x^2+x\right)-2x=8\)

\(\Leftrightarrow2x^2+2x-2x=8\)

\(\Leftrightarrow2x^2=8\Leftrightarrow x^2=4\Leftrightarrow\left[\begin{array}{nghiempt}x=2\\x=-2\end{array}\right.\)

Answer 2

a) 2 . ( x^2 - x ) - 2x^2 = 3

    2x²-2x-2x²=0

    -2x=0

     x=0

Vậy x=0

b) 2 . ( x^2 + x ) - 2x = 8

    2x²+2x-2x=8

    2x²=8

    x²=4=2²=(-2)²

Vậy x=2;-2