300=2b^2+14b-20

Solution for 300=2b^2+14b-20 equation:

300=2b^2+14b-20

We move all terms to the left:

300-(2b^2+14b-20)=0

We get rid of parentheses

-2b^2-14b+20+300=0

We add all the numbers together, and all the variables

-2b^2-14b+320=0

a = -2; b = -14; c = +320;
Δ = b2-4ac
Δ = -142-4·(-2)·320
Δ = 2756
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{2756}=\sqrt{4*689}=\sqrt{4}*\sqrt{689}=2\sqrt{689}$
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-14)-2\sqrt{689}}{2*-2}=\frac{14-2\sqrt{689}}{-4}
$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-14)+2\sqrt{689}}{2*-2}=\frac{14+2\sqrt{689}}{-4}
$