7x2-140x-63=0

Solution for 7x2-140x-63=0 equation:

7x^2-140x-63=0

a = 7; b = -140; c = -63;
Δ = b2-4ac
Δ = -1402-4·7·(-63)
Δ = 21364
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:

$\sqrt{\Delta}=\sqrt{21364}=\sqrt{196*109}=\sqrt{196}*\sqrt{109}=14\sqrt{109}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-140)-14\sqrt{109}}{2*7}=\frac{140-14\sqrt{109}}{14}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-140)+14\sqrt{109}}{2*7}=\frac{140+14\sqrt{109}}{14}
$