(5r+6)(5r-6)=

Solution for (5r+6)(5r-6)= equation:

Simplifying
(5r + 6)(5r + -6) = 0

Reorder the terms:
(6 + 5r)(5r + -6) = 0

Reorder the terms:
(6 + 5r)(-6 + 5r) = 0

Multiply (6 + 5r) * (-6 + 5r)
(6(-6 + 5r) + 5r * (-6 + 5r)) = 0
((-6 * 6 + 5r * 6) + 5r * (-6 + 5r)) = 0
((-36 + 30r) + 5r * (-6 + 5r)) = 0
(-36 + 30r + (-6 * 5r + 5r * 5r)) = 0
(-36 + 30r + (-30r + 25r2)) = 0

Combine like terms: 30r + -30r = 0
(-36 + 0 + 25r2) = 0
(-36 + 25r2) = 0

Solving
-36 + 25r2 = 0

Solving for variable 'r'.

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

Add '36' to each side of the equation.
-36 + 36 + 25r2 = 0 + 36

Combine like terms: -36 + 36 = 0
0 + 25r2 = 0 + 36
25r2 = 0 + 36

Combine like terms: 0 + 36 = 36
25r2 = 36

Divide each side by '25'.
r2 = 1.44

Simplifying
r2 = 1.44

Take the square root of each side:
r = {-1.2, 1.2}