X*4x=140

Solution for X*4x=140 equation:

X*4X=140

We move all terms to the left:

X*4X-(140)=0

Wy multiply elements

4X^2-140=0

a = 4; b = 0; c = -140;
Δ = b2-4ac
Δ = 02-4·4·(-140)
Δ = 2240
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:

$\sqrt{\Delta}=\sqrt{2240}=\sqrt{64*35}=\sqrt{64}*\sqrt{35}=8\sqrt{35}$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-8\sqrt{35}}{2*4}=\frac{0-8\sqrt{35}}{8}
=-\frac{8\sqrt{35}}{8}
=-\sqrt{35}
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+8\sqrt{35}}{2*4}=\frac{0+8\sqrt{35}}{8}
=\frac{8\sqrt{35}}{8}
=\sqrt{35}
$