(5+4a)(4a-5)=

Solution for (5+4a)(4a-5)= equation:

Simplifying
(5 + 4a)(4a + -5) = 0

Reorder the terms:
(5 + 4a)(-5 + 4a) = 0

Multiply (5 + 4a) * (-5 + 4a)
(5(-5 + 4a) + 4a * (-5 + 4a)) = 0
((-5 * 5 + 4a * 5) + 4a * (-5 + 4a)) = 0
((-25 + 20a) + 4a * (-5 + 4a)) = 0
(-25 + 20a + (-5 * 4a + 4a * 4a)) = 0
(-25 + 20a + (-20a + 16a2)) = 0

Combine like terms: 20a + -20a = 0
(-25 + 0 + 16a2) = 0
(-25 + 16a2) = 0

Solving
-25 + 16a2 = 0

Solving for variable 'a'.

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

Add '25' to each side of the equation.
-25 + 25 + 16a2 = 0 + 25

Combine like terms: -25 + 25 = 0
0 + 16a2 = 0 + 25
16a2 = 0 + 25

Combine like terms: 0 + 25 = 25
16a2 = 25

Divide each side by '16'.
a2 = 1.5625

Simplifying
a2 = 1.5625

Take the square root of each side:
a = {-1.25, 1.25}