-4(x)=2x2-1

Solution for -4(x)=2x2-1 equation:

-4(x)=2x^2-1

We move all terms to the left:

-4(x)-(2x^2-1)=0

We get rid of parentheses

-2x^2-4x+1=0

a = -2; b = -4; c = +1;
Δ = b2-4ac
Δ = -42-4·(-2)·1
Δ = 24
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{24}=\sqrt{4*6}=\sqrt{4}*\sqrt{6}=2\sqrt{6}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-4)-2\sqrt{6}}{2*-2}=\frac{4-2\sqrt{6}}{-4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-4)+2\sqrt{6}}{2*-2}=\frac{4+2\sqrt{6}}{-4}
$