40=1.5(x^2)

Solution for 40=1.5(x^2) equation:

40=1.5(x^2)

We move all terms to the left:

40-(1.5(x^2))=0

We get rid of parentheses

-1.5x^2+40=0

a = -1.5; b = 0; c = +40;
Δ = b2-4ac
Δ = 02-4·(-1.5)·40
Δ = 240
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:

$\sqrt{\Delta}=\sqrt{240}=\sqrt{16*15}=\sqrt{16}*\sqrt{15}=4\sqrt{15}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-4\sqrt{15}}{2*-1.5}=\frac{0-4\sqrt{15}}{-3}
=-\frac{4\sqrt{15}}{-3}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+4\sqrt{15}}{2*-1.5}=\frac{0+4\sqrt{15}}{-3}
=\frac{4\sqrt{15}}{-3}
$