7r^2+46r=21

Solution for 7r^2+46r=21 equation:

Simplifying
7r2 + 46r = 21

Reorder the terms:
46r + 7r2 = 21

Solving
46r + 7r2 = 21

Solving for variable 'r'.

Reorder the terms:
-21 + 46r + 7r2 = 21 + -21

Combine like terms: 21 + -21 = 0
-21 + 46r + 7r2 = 0

Factor a trinomial.
(-7 + -1r)(3 + -7r) = 0

Subproblem 1
Set the factor '(-7 + -1r)' equal to zero and attempt to solve:

Simplifying
-7 + -1r = 0

Solving
-7 + -1r = 0

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

Add '7' to each side of the equation.
-7 + 7 + -1r = 0 + 7

Combine like terms: -7 + 7 = 0
0 + -1r = 0 + 7
-1r = 0 + 7

Combine like terms: 0 + 7 = 7
-1r = 7

Divide each side by '-1'.
r = -7

Simplifying
r = -7
Subproblem 2
Set the factor '(3 + -7r)' equal to zero and attempt to solve:

Simplifying
3 + -7r = 0

Solving
3 + -7r = 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 + -7r = 0 + -3

Combine like terms: 3 + -3 = 0
0 + -7r = 0 + -3
-7r = 0 + -3

Combine like terms: 0 + -3 = -3
-7r = -3

Divide each side by '-7'.
r = 0.4285714286

Simplifying
r = 0.4285714286
Solution
r = {-7, 0.4285714286}