-r^2=4-4r

Solution for -r^2=4-4r equation:

Simplifying
-1r2 = 4 + -4r

Solving
-1r2 = 4 + -4r

Solving for variable 'r'.

Reorder the terms:
-4 + 4r + -1r2 = 4 + -4r + -4 + 4r

Reorder the terms:
-4 + 4r + -1r2 = 4 + -4 + -4r + 4r

Combine like terms: 4 + -4 = 0
-4 + 4r + -1r2 = 0 + -4r + 4r
-4 + 4r + -1r2 = -4r + 4r

Combine like terms: -4r + 4r = 0
-4 + 4r + -1r2 = 0

Factor a trinomial.
(-2 + r)(2 + -1r) = 0

Subproblem 1
Set the factor '(-2 + r)' equal to zero and attempt to solve:

Simplifying
-2 + r = 0

Solving
-2 + r = 0

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

Add '2' to each side of the equation.
-2 + 2 + r = 0 + 2

Combine like terms: -2 + 2 = 0
0 + r = 0 + 2
r = 0 + 2

Combine like terms: 0 + 2 = 2
r = 2

Simplifying
r = 2
Subproblem 2
Set the factor '(2 + -1r)' equal to zero and attempt to solve:

Simplifying
2 + -1r = 0

Solving
2 + -1r = 0

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

Add '-2' to each side of the equation.
2 + -2 + -1r = 0 + -2

Combine like terms: 2 + -2 = 0
0 + -1r = 0 + -2
-1r = 0 + -2

Combine like terms: 0 + -2 = -2
-1r = -2

Divide each side by '-1'.
r = 2

Simplifying
r = 2
Solution
r = {2, 2}