7a^3-21a^2=

Solution for 7a^3-21a^2= equation:

Simplifying
7a3 + -21a2 = 0

Reorder the terms:
-21a2 + 7a3 = 0

Solving
-21a2 + 7a3 = 0

Solving for variable 'a'.

Factor out the Greatest Common Factor (GCF), '7a2'.
7a2(-3 + a) = 0

Ignore the factor 7.
Subproblem 1
Set the factor 'a2' equal to zero and attempt to solve:

Simplifying
a2 = 0

Solving
a2 = 0

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

Simplifying
a2 = 0

Take the square root of each side:
a = {0}
Subproblem 2
Set the factor '(-3 + a)' equal to zero and attempt to solve:

Simplifying
-3 + a = 0

Solving
-3 + a = 0

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

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

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

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

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