3(r-5)(r+5)=0

Solution for 3(r-5)(r+5)=0 equation:

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

Reorder the terms:
3(-5 + r)(r + 5) = 0

Reorder the terms:
3(-5 + r)(5 + r) = 0

Multiply (-5 + r) * (5 + r)
3(-5(5 + r) + r(5 + r)) = 0
3((5 * -5 + r * -5) + r(5 + r)) = 0
3((-25 + -5r) + r(5 + r)) = 0
3(-25 + -5r + (5 * r + r * r)) = 0
3(-25 + -5r + (5r + r2)) = 0

Combine like terms: -5r + 5r = 0
3(-25 + 0 + r2) = 0
3(-25 + r2) = 0
(-25 * 3 + r2 * 3) = 0
(-75 + 3r2) = 0

Solving
-75 + 3r2 = 0

Solving for variable 'r'.

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

Add '75' to each side of the equation.
-75 + 75 + 3r2 = 0 + 75

Combine like terms: -75 + 75 = 0
0 + 3r2 = 0 + 75
3r2 = 0 + 75

Combine like terms: 0 + 75 = 75
3r2 = 75

Divide each side by '3'.
r2 = 25

Simplifying
r2 = 25

Take the square root of each side:
r = {-5, 5}