20+23a-21a^2=

Solution for 20+23a-21a^2= equation:

Simplifying
20 + 23a + -21a2 = 0

Solving
20 + 23a + -21a2 = 0

Solving for variable 'a'.

Factor a trinomial.
(5 + -3a)(4 + 7a) = 0

Subproblem 1
Set the factor '(5 + -3a)' equal to zero and attempt to solve:

Simplifying
5 + -3a = 0

Solving
5 + -3a = 0

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

Add '-5' to each side of the equation.
5 + -5 + -3a = 0 + -5

Combine like terms: 5 + -5 = 0
0 + -3a = 0 + -5
-3a = 0 + -5

Combine like terms: 0 + -5 = -5
-3a = -5

Divide each side by '-3'.
a = 1.666666667

Simplifying
a = 1.666666667
Subproblem 2
Set the factor '(4 + 7a)' equal to zero and attempt to solve:

Simplifying
4 + 7a = 0

Solving
4 + 7a = 0

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

Add '-4' to each side of the equation.
4 + -4 + 7a = 0 + -4

Combine like terms: 4 + -4 = 0
0 + 7a = 0 + -4
7a = 0 + -4

Combine like terms: 0 + -4 = -4
7a = -4

Divide each side by '7'.
a = -0.5714285714

Simplifying
a = -0.5714285714
Solution
a = {1.666666667, -0.5714285714}