4x2-30x=28

Solution for 4x2-30x=28 equation:

4x^2-30x=28

We move all terms to the left:

4x^2-30x-(28)=0

a = 4; b = -30; c = -28;
Δ = b2-4ac
Δ = -302-4·4·(-28)
Δ = 1348
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:

$\sqrt{\Delta}=\sqrt{1348}=\sqrt{4*337}=\sqrt{4}*\sqrt{337}=2\sqrt{337}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-30)-2\sqrt{337}}{2*4}=\frac{30-2\sqrt{337}}{8}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-30)+2\sqrt{337}}{2*4}=\frac{30+2\sqrt{337}}{8}
$