X^2+7x=87,75

Solution for X^2+7x=87,75 equation:

X^2+7X=87.75

We move all terms to the left:

X^2+7X-(87.75)=0

We add all the numbers together, and all the variables

X^2+7X-87.75=0

a = 1; b = 7; c = -87.75;
Δ = b2-4ac
Δ = 72-4·1·(-87.75)
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{-(7)-20}{2*1}=\frac{-27}{2}
=-13+1/2
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(7)+20}{2*1}=\frac{13}{2}
=6+1/2
$