(7y^2-7y+9)-(8y^2-7y+5)=

Solution for (7y^2-7y+9)-(8y^2-7y+5)= equation:

Simplifying
(7y2 + -7y + 9) + -1(8y2 + -7y + 5) = 0

Reorder the terms:
(9 + -7y + 7y2) + -1(8y2 + -7y + 5) = 0

Remove parenthesis around (9 + -7y + 7y2)
9 + -7y + 7y2 + -1(8y2 + -7y + 5) = 0

Reorder the terms:
9 + -7y + 7y2 + -1(5 + -7y + 8y2) = 0
9 + -7y + 7y2 + (5 * -1 + -7y * -1 + 8y2 * -1) = 0
9 + -7y + 7y2 + (-5 + 7y + -8y2) = 0

Reorder the terms:
9 + -5 + -7y + 7y + 7y2 + -8y2 = 0

Combine like terms: 9 + -5 = 4
4 + -7y + 7y + 7y2 + -8y2 = 0

Combine like terms: -7y + 7y = 0
4 + 0 + 7y2 + -8y2 = 0
4 + 7y2 + -8y2 = 0

Combine like terms: 7y2 + -8y2 = -1y2
4 + -1y2 = 0

Solving
4 + -1y2 = 0

Solving for variable 'y'.

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

Add '-4' to each side of the equation.
4 + -4 + -1y2 = 0 + -4

Combine like terms: 4 + -4 = 0
0 + -1y2 = 0 + -4
-1y2 = 0 + -4

Combine like terms: 0 + -4 = -4
-1y2 = -4

Divide each side by '-1'.
y2 = 4

Simplifying
y2 = 4

Take the square root of each side:
y = {-2, 2}