5x^2+70x=245=0

Solution for 5x^2+70x=245=0 equation:

5x^2+70x=245=0

We move all terms to the left:

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}
$