5b*4b=18

Solution for 5b*4b=18 equation:

5b*4b=18

We move all terms to the left:

5b*4b-(18)=0

Wy multiply elements

20b^2-18=0

a = 20; b = 0; c = -18;
Δ = b2-4ac
Δ = 02-4·20·(-18)
Δ = 1440
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{1440}=\sqrt{144*10}=\sqrt{144}*\sqrt{10}=12\sqrt{10}$
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-12\sqrt{10}}{2*20}=\frac{0-12\sqrt{10}}{40}
=-\frac{12\sqrt{10}}{40}
=-\frac{3\sqrt{10}}{10}
$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+12\sqrt{10}}{2*20}=\frac{0+12\sqrt{10}}{40}
=\frac{12\sqrt{10}}{40}
=\frac{3\sqrt{10}}{10}
$