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

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

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

Multiply (4a + 5c) * (4a + -5c)
(4a * (4a + -5c) + 5c * (4a + -5c)) = 0
((4a * 4a + -5c * 4a) + 5c * (4a + -5c)) = 0

Reorder the terms:
((-20ac + 16a2) + 5c * (4a + -5c)) = 0
((-20ac + 16a2) + 5c * (4a + -5c)) = 0
(-20ac + 16a2 + (4a * 5c + -5c * 5c)) = 0
(-20ac + 16a2 + (20ac + -25c2)) = 0

Reorder the terms:
(-20ac + 20ac + 16a2 + -25c2) = 0

Combine like terms: -20ac + 20ac = 0
(0 + 16a2 + -25c2) = 0
(16a2 + -25c2) = 0

Solving
16a2 + -25c2 = 0

Solving for variable 'a'.

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

Add '25c2' to each side of the equation.
16a2 + -25c2 + 25c2 = 0 + 25c2

Combine like terms: -25c2 + 25c2 = 0
16a2 + 0 = 0 + 25c2
16a2 = 0 + 25c2
Remove the zero:
16a2 = 25c2

Divide each side by '16'.
a2 = 1.5625c2

Simplifying
a2 = 1.5625c2

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