7x^2+8=15x

Solution for 7x^2+8=15x equation:

7x^2+8=15x

We move all terms to the left:

7x^2+8-(15x)=0

a = 7; b = -15; c = +8;
Δ = b2-4ac
Δ = -152-4·7·8
Δ = 1
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1}=1$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-15)-1}{2*7}=\frac{14}{14}
=1
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-15)+1}{2*7}=\frac{16}{14}
=1+1/7
$