70x^2+49x+30x+21=90

Solution for 70x^2+49x+30x+21=90 equation:

70x^2+49x+30x+21=90

We move all terms to the left:

70x^2+49x+30x+21-(90)=0

We add all the numbers together, and all the variables

70x^2+79x-69=0

a = 70; b = 79; c = -69;
Δ = b2-4ac
Δ = 792-4·70·(-69)
Δ = 25561
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{-(79)-\sqrt{25561}}{2*70}=\frac{-79-\sqrt{25561}}{140}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(79)+\sqrt{25561}}{2*70}=\frac{-79+\sqrt{25561}}{140}
$