-7x^2=9x^2-25

Solution for -7x^2=9x^2-25 equation:

-7x^2=9x^2-25

We move all terms to the left:

-7x^2-(9x^2-25)=0

We get rid of parentheses

-7x^2-9x^2+25=0

We add all the numbers together, and all the variables

-16x^2+25=0

a = -16; b = 0; c = +25;
Δ = b2-4ac
Δ = 02-4·(-16)·25
Δ = 1600
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1600}=40$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-40}{2*-16}=\frac{-40}{-32}
=1+1/4
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+40}{2*-16}=\frac{40}{-32}
=-1+1/4
$