3A^2-15A-42=

Solution for 3A^2-15A-42= equation:

Simplifying
3A2 + -15A + -42 = 0

Reorder the terms:
-42 + -15A + 3A2 = 0

Solving
-42 + -15A + 3A2 = 0

Solving for variable 'A'.

Factor out the Greatest Common Factor (GCF), '3'.
3(-14 + -5A + A2) = 0

Factor a trinomial.
3((-2 + -1A)(7 + -1A)) = 0

Ignore the factor 3.
Subproblem 1
Set the factor '(-2 + -1A)' equal to zero and attempt to solve:

Simplifying
-2 + -1A = 0

Solving
-2 + -1A = 0

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

Add '2' to each side of the equation.
-2 + 2 + -1A = 0 + 2

Combine like terms: -2 + 2 = 0
0 + -1A = 0 + 2
-1A = 0 + 2

Combine like terms: 0 + 2 = 2
-1A = 2

Divide each side by '-1'.
A = -2

Simplifying
A = -2
Subproblem 2
Set the factor '(7 + -1A)' equal to zero and attempt to solve:

Simplifying
7 + -1A = 0

Solving
7 + -1A = 0

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

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

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

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

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

Simplifying
A = 7
Solution
A = {-2, 7}