7x^2+2x=98

Solution for 7x^2+2x=98 equation:

7x^2+2x=98

We move all terms to the left:

7x^2+2x-(98)=0

a = 7; b = 2; c = -98;
Δ = b2-4ac
Δ = 22-4·7·(-98)
Δ = 2748
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:

$\sqrt{\Delta}=\sqrt{2748}=\sqrt{4*687}=\sqrt{4}*\sqrt{687}=2\sqrt{687}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(2)-2\sqrt{687}}{2*7}=\frac{-2-2\sqrt{687}}{14}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(2)+2\sqrt{687}}{2*7}=\frac{-2+2\sqrt{687}}{14}
$