7b^2=21b

Solution for 7b^2=21b equation:

Simplifying
7b2 = 21b

Solving
7b2 = 21b

Solving for variable 'b'.

Reorder the terms:
-21b + 7b2 = 21b + -21b

Combine like terms: 21b + -21b = 0
-21b + 7b2 = 0

Factor out the Greatest Common Factor (GCF), '7b'.
7b(-3 + b) = 0

Ignore the factor 7.
Subproblem 1
Set the factor 'b' equal to zero and attempt to solve:

Simplifying
b = 0

Solving
b = 0

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

Simplifying
b = 0
Subproblem 2
Set the factor '(-3 + b)' equal to zero and attempt to solve:

Simplifying
-3 + b = 0

Solving
-3 + b = 0

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

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

Combine like terms: -3 + 3 = 0
0 + b = 0 + 3
b = 0 + 3

Combine like terms: 0 + 3 = 3
b = 3

Simplifying
b = 3
Solution
b = {0, 3}