10r^2-81r+8=0

Solution for 10r^2-81r+8=0 equation:

Simplifying
10r2 + -81r + 8 = 0

Reorder the terms:
8 + -81r + 10r2 = 0

Solving
8 + -81r + 10r2 = 0

Solving for variable 'r'.

Factor a trinomial.
(1 + -10r)(8 + -1r) = 0

Subproblem 1
Set the factor '(1 + -10r)' equal to zero and attempt to solve:

Simplifying
1 + -10r = 0

Solving
1 + -10r = 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 + -10r = 0 + -1

Combine like terms: 1 + -1 = 0
0 + -10r = 0 + -1
-10r = 0 + -1

Combine like terms: 0 + -1 = -1
-10r = -1

Divide each side by '-10'.
r = 0.1

Simplifying
r = 0.1
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 = {0.1, 8}