x2+15x=43.75

Solution for x2+15x=43.75 equation:

x2+15x=43.75

We move all terms to the left:

x2+15x-(43.75)=0

We add all the numbers together, and all the variables

x^2+15x-43.75=0

a = 1; b = 15; c = -43.75;
Δ = b2-4ac
Δ = 152-4·1·(-43.75)
Δ = 400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{400}=20$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(15)-20}{2*1}=\frac{-35}{2}
=-17+1/2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(15)+20}{2*1}=\frac{5}{2}
=2+1/2
$