2r^2-39=7r

Solution for 2r^2-39=7r equation:

Simplifying
2r2 + -39 = 7r

Reorder the terms:
-39 + 2r2 = 7r

Solving
-39 + 2r2 = 7r

Solving for variable 'r'.

Reorder the terms:
-39 + -7r + 2r2 = 7r + -7r

Combine like terms: 7r + -7r = 0
-39 + -7r + 2r2 = 0

Factor a trinomial.
(-3 + -1r)(13 + -2r) = 0

Subproblem 1
Set the factor '(-3 + -1r)' equal to zero and attempt to solve:

Simplifying
-3 + -1r = 0

Solving
-3 + -1r = 0

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

Add '3' to each side of the equation.
-3 + 3 + -1r = 0 + 3

Combine like terms: -3 + 3 = 0
0 + -1r = 0 + 3
-1r = 0 + 3

Combine like terms: 0 + 3 = 3
-1r = 3

Divide each side by '-1'.
r = -3

Simplifying
r = -3
Subproblem 2
Set the factor '(13 + -2r)' equal to zero and attempt to solve:

Simplifying
13 + -2r = 0

Solving
13 + -2r = 0

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

Add '-13' to each side of the equation.
13 + -13 + -2r = 0 + -13

Combine like terms: 13 + -13 = 0
0 + -2r = 0 + -13
-2r = 0 + -13

Combine like terms: 0 + -13 = -13
-2r = -13

Divide each side by '-2'.
r = 6.5

Simplifying
r = 6.5
Solution
r = {-3, 6.5}