d^2=1.5^2+1.2^2

Solution for d^2=1.5^2+1.2^2 equation:

d^2=1.5^2+1.2^2

We move all terms to the left:

d^2-(1.5^2+1.2^2)=0

We add all the numbers together, and all the variables

d^2-3.69=0

a = 1; b = 0; c = -3.69;
Δ = b2-4ac
Δ = 02-4·1·(-3.69)
Δ = 14.76
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$d_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$d_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$d_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-\sqrt{14.76}}{2*1}=\frac{0-\sqrt{14.76}}{2}
=-\frac{\sqrt{}}{2}
$
$d_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+\sqrt{14.76}}{2*1}=\frac{0+\sqrt{14.76}}{2}
=\frac{\sqrt{}}{2}
$