(7y^2-5y+4)-(2y^2-5y+7)=

Solution for (7y^2-5y+4)-(2y^2-5y+7)= equation:

Simplifying
(7y2 + -5y + 4) + -1(2y2 + -5y + 7) = 0

Reorder the terms:
(4 + -5y + 7y2) + -1(2y2 + -5y + 7) = 0

Remove parenthesis around (4 + -5y + 7y2)
4 + -5y + 7y2 + -1(2y2 + -5y + 7) = 0

Reorder the terms:
4 + -5y + 7y2 + -1(7 + -5y + 2y2) = 0
4 + -5y + 7y2 + (7 * -1 + -5y * -1 + 2y2 * -1) = 0
4 + -5y + 7y2 + (-7 + 5y + -2y2) = 0

Reorder the terms:
4 + -7 + -5y + 5y + 7y2 + -2y2 = 0

Combine like terms: 4 + -7 = -3
-3 + -5y + 5y + 7y2 + -2y2 = 0

Combine like terms: -5y + 5y = 0
-3 + 0 + 7y2 + -2y2 = 0
-3 + 7y2 + -2y2 = 0

Combine like terms: 7y2 + -2y2 = 5y2
-3 + 5y2 = 0

Solving
-3 + 5y2 = 0

Solving for variable 'y'.

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

Add '3' to each side of the equation.
-3 + 3 + 5y2 = 0 + 3

Combine like terms: -3 + 3 = 0
0 + 5y2 = 0 + 3
5y2 = 0 + 3

Combine like terms: 0 + 3 = 3
5y2 = 3

Divide each side by '5'.
y2 = 0.6

Simplifying
y2 = 0.6

Take the square root of each side:
y = {-0.774596669, 0.774596669}