245=5x^2+70x

Solution for 245=5x^2+70x equation:

245=5x^2+70x

We move all terms to the left:

245-(5x^2+70x)=0

We get rid of parentheses

-5x^2-70x+245=0

a = -5; b = -70; c = +245;
Δ = b2-4ac
Δ = -702-4·(-5)·245
Δ = 9800
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{9800}=\sqrt{4900*2}=\sqrt{4900}*\sqrt{2}=70\sqrt{2}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-70)-70\sqrt{2}}{2*-5}=\frac{70-70\sqrt{2}}{-10}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-70)+70\sqrt{2}}{2*-5}=\frac{70+70\sqrt{2}}{-10}
$