(x+7)*x=210

Solution for (x+7)*x=210 equation:

(x+7)*x=210

We move all terms to the left:

(x+7)*x-(210)=0

We multiply parentheses

x^2+7x-210=0

a = 1; b = 7; c = -210;
Δ = b2-4ac
Δ = 72-4·1·(-210)
Δ = 889
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(7)-\sqrt{889}}{2*1}=\frac{-7-\sqrt{889}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(7)+\sqrt{889}}{2*1}=\frac{-7+\sqrt{889}}{2}
$