7d^2+5d-(5d+20)-8=0

Solution for 7d^2+5d-(5d+20)-8=0 equation:

Simplifying
7d2 + 5d + -1(5d + 20) + -8 = 0

Reorder the terms:
7d2 + 5d + -1(20 + 5d) + -8 = 0
7d2 + 5d + (20 * -1 + 5d * -1) + -8 = 0
7d2 + 5d + (-20 + -5d) + -8 = 0

Reorder the terms:
-20 + -8 + 5d + -5d + 7d2 = 0

Combine like terms: -20 + -8 = -28
-28 + 5d + -5d + 7d2 = 0

Combine like terms: 5d + -5d = 0
-28 + 0 + 7d2 = 0
-28 + 7d2 = 0

Solving
-28 + 7d2 = 0

Solving for variable 'd'.

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

Add '28' to each side of the equation.
-28 + 28 + 7d2 = 0 + 28

Combine like terms: -28 + 28 = 0
0 + 7d2 = 0 + 28
7d2 = 0 + 28

Combine like terms: 0 + 28 = 28
7d2 = 28

Divide each side by '7'.
d2 = 4

Simplifying
d2 = 4

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