8x2-55x=7

Solution for 8x2-55x=7 equation:

8x^2-55x=7

We move all terms to the left:

8x^2-55x-(7)=0

a = 8; b = -55; c = -7;
Δ = b2-4ac
Δ = -552-4·8·(-7)
Δ = 3249
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{3249}=57$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-55)-57}{2*8}=\frac{-2}{16}
=-1/8
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-55)+57}{2*8}=\frac{112}{16}
=7
$