5x^2-7x-15=-8-9x

Solution for 5x^2-7x-15=-8-9x equation:

5x^2-7x-15=-8-9x

We move all terms to the left:

5x^2-7x-15-(-8-9x)=0

We add all the numbers together, and all the variables

5x^2-7x-(-9x-8)-15=0

We get rid of parentheses

5x^2-7x+9x+8-15=0

We add all the numbers together, and all the variables

5x^2+2x-7=0

a = 5; b = 2; c = -7;
Δ = b2-4ac
Δ = 22-4·5·(-7)
Δ = 144
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{144}=12$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(2)-12}{2*5}=\frac{-14}{10}
=-1+2/5
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(2)+12}{2*5}=\frac{10}{10}
=1
$