r^2=8r+9

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Solution for r^2=8r+9 equation:


Simplifying
r2 = 8r + 9

Reorder the terms:
r2 = 9 + 8r

Solving
r2 = 9 + 8r

Solving for variable 'r'.

Reorder the terms:
-9 + -8r + r2 = 9 + 8r + -9 + -8r

Reorder the terms:
-9 + -8r + r2 = 9 + -9 + 8r + -8r

Combine like terms: 9 + -9 = 0
-9 + -8r + r2 = 0 + 8r + -8r
-9 + -8r + r2 = 8r + -8r

Combine like terms: 8r + -8r = 0
-9 + -8r + r2 = 0

Factor a trinomial.
(-1 + -1r)(9 + -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 '(9 + -1r)' equal to zero and attempt to solve: Simplifying 9 + -1r = 0 Solving 9 + -1r = 0 Move all terms containing r to the left, all other terms to the right. Add '-9' to each side of the equation. 9 + -9 + -1r = 0 + -9 Combine like terms: 9 + -9 = 0 0 + -1r = 0 + -9 -1r = 0 + -9 Combine like terms: 0 + -9 = -9 -1r = -9 Divide each side by '-1'. r = 9 Simplifying r = 9

Solution

r = {-1, 9}

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