7x*8x=100

Solution for 7x*8x=100 equation:

7x*8x=100

We move all terms to the left:

7x*8x-(100)=0

Wy multiply elements

56x^2-100=0

a = 56; b = 0; c = -100;
Δ = b2-4ac
Δ = 02-4·56·(-100)
Δ = 22400
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:

$\sqrt{\Delta}=\sqrt{22400}=\sqrt{1600*14}=\sqrt{1600}*\sqrt{14}=40\sqrt{14}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-40\sqrt{14}}{2*56}=\frac{0-40\sqrt{14}}{112}
=-\frac{40\sqrt{14}}{112}
=-\frac{5\sqrt{14}}{14}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+40\sqrt{14}}{2*56}=\frac{0+40\sqrt{14}}{112}
=\frac{40\sqrt{14}}{112}
=\frac{5\sqrt{14}}{14}
$