(16x)^2+(9x)^2=70^2

Solution for (16x)^2+(9x)^2=70^2 equation:

(16x)^2+(9x)^2=70^2

We move all terms to the left:

(16x)^2+(9x)^2-(70^2)=0

We add all the numbers together, and all the variables

25x^2-4900=0

a = 25; b = 0; c = -4900;
Δ = b2-4ac
Δ = 02-4·25·(-4900)
Δ = 490000
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{490000}=700$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-700}{2*25}=\frac{-700}{50}
=-14
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+700}{2*25}=\frac{700}{50}
=14
$