-27=-10x-7x^2

Solution for -27=-10x-7x^2 equation:

-27=-10x-7x^2

We move all terms to the left:

-27-(-10x-7x^2)=0

We get rid of parentheses

7x^2+10x-27=0

a = 7; b = 10; c = -27;
Δ = b2-4ac
Δ = 102-4·7·(-27)
Δ = 856
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:

$\sqrt{\Delta}=\sqrt{856}=\sqrt{4*214}=\sqrt{4}*\sqrt{214}=2\sqrt{214}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(10)-2\sqrt{214}}{2*7}=\frac{-10-2\sqrt{214}}{14}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(10)+2\sqrt{214}}{2*7}=\frac{-10+2\sqrt{214}}{14}
$