0=7x^2-30x+8

Solution for 0=7x^2-30x+8 equation:

0=7x^2-30x+8

We move all terms to the left:

0-(7x^2-30x+8)=0

We add all the numbers together, and all the variables

-(7x^2-30x+8)=0

We get rid of parentheses

-7x^2+30x-8=0

a = -7; b = 30; c = -8;
Δ = b2-4ac
Δ = 302-4·(-7)·(-8)
Δ = 676
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{676}=26$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(30)-26}{2*-7}=\frac{-56}{-14}
=+4
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(30)+26}{2*-7}=\frac{-4}{-14}
=2/7
$