7x^2+9x^2=-6x^2-7x

Solution for 7x^2+9x^2=-6x^2-7x equation:

7x^2+9x^2=-6x^2-7x

We move all terms to the left:

7x^2+9x^2-(-6x^2-7x)=0

We add all the numbers together, and all the variables

16x^2-(-6x^2-7x)=0

We get rid of parentheses

16x^2+6x^2+7x=0

We add all the numbers together, and all the variables

22x^2+7x=0

a = 22; b = 7; c = 0;
Δ = b2-4ac
Δ = 72-4·22·0
Δ = 49
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{49}=7$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(7)-7}{2*22}=\frac{-14}{44}
=-7/22
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(7)+7}{2*22}=\frac{0}{44}
=0
$