(4y+8)(4y-8)=71

Solution for (4y+8)(4y-8)=71 equation:

Simplifying
(4y + 8)(4y + -8) = 71

Reorder the terms:
(8 + 4y)(4y + -8) = 71

Reorder the terms:
(8 + 4y)(-8 + 4y) = 71

Multiply (8 + 4y) * (-8 + 4y)
(8(-8 + 4y) + 4y * (-8 + 4y)) = 71
((-8 * 8 + 4y * 8) + 4y * (-8 + 4y)) = 71
((-64 + 32y) + 4y * (-8 + 4y)) = 71
(-64 + 32y + (-8 * 4y + 4y * 4y)) = 71
(-64 + 32y + (-32y + 16y2)) = 71

Combine like terms: 32y + -32y = 0
(-64 + 0 + 16y2) = 71
(-64 + 16y2) = 71

Solving
-64 + 16y2 = 71

Solving for variable 'y'.

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

Add '64' to each side of the equation.
-64 + 64 + 16y2 = 71 + 64

Combine like terms: -64 + 64 = 0
0 + 16y2 = 71 + 64
16y2 = 71 + 64

Combine like terms: 71 + 64 = 135
16y2 = 135

Divide each side by '16'.
y2 = 8.4375

Simplifying
y2 = 8.4375

Take the square root of each side:
y = {-2.90473751, 2.90473751}