r(r-7)=8

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Solution for r(r-7)=8 equation: 


Simplifying
r(r + -7) = 8

Reorder the terms:
r(-7 + r) = 8
(-7 * r + r * r) = 8
(-7r + r2) = 8

Solving
-7r + r2 = 8

Solving for variable 'r'.

Reorder the terms:
-8 + -7r + r2 = 8 + -8

Combine like terms: 8 + -8 = 0
-8 + -7r + r2 = 0

Factor a trinomial.
(-1 + -1r)(8 + -1r) = 0


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

Simplifying
-1 + -1r = 0

Solving
-1 + -1r = 0

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

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

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

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

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

Simplifying
r = -1

Subproblem 2
Set the factor '(8 + -1r)' equal to zero and attempt to solve:

Simplifying
8 + -1r = 0

Solving
8 + -1r = 0

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

Add '-8' to each side of the equation.
8 + -8 + -1r = 0 + -8

Combine like terms: 8 + -8 = 0
0 + -1r = 0 + -8
-1r = 0 + -8

Combine like terms: 0 + -8 = -8
-1r = -8

Divide each side by '-1'.
r = 8

Simplifying
r = 8
Solution
r = {-1, 8}

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