(2z^2+13)-(9z^2+9)=

Solution for (2z^2+13)-(9z^2+9)= equation:

Simplifying
(2z2 + 13) + -1(9z2 + 9) = 0

Reorder the terms:
(13 + 2z2) + -1(9z2 + 9) = 0

Remove parenthesis around (13 + 2z2)
13 + 2z2 + -1(9z2 + 9) = 0

Reorder the terms:
13 + 2z2 + -1(9 + 9z2) = 0
13 + 2z2 + (9 * -1 + 9z2 * -1) = 0
13 + 2z2 + (-9 + -9z2) = 0

Reorder the terms:
13 + -9 + 2z2 + -9z2 = 0

Combine like terms: 13 + -9 = 4
4 + 2z2 + -9z2 = 0

Combine like terms: 2z2 + -9z2 = -7z2
4 + -7z2 = 0

Solving
4 + -7z2 = 0

Solving for variable 'z'.

Move all terms containing z to the left, all other terms to the right.

Add '-4' to each side of the equation.
4 + -4 + -7z2 = 0 + -4

Combine like terms: 4 + -4 = 0
0 + -7z2 = 0 + -4
-7z2 = 0 + -4

Combine like terms: 0 + -4 = -4
-7z2 = -4

Divide each side by '-7'.
z2 = 0.5714285714

Simplifying
z2 = 0.5714285714

Take the square root of each side:
z = {-0.755928946, 0.755928946}