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

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

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

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

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

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

Combine like terms: -5a + 4a = -1a
a + -4 + (-20 + -1a + a2) = 0

Reorder the terms:
-4 + -20 + a + -1a + a2 = 0

Combine like terms: -4 + -20 = -24
-24 + a + -1a + a2 = 0

Combine like terms: a + -1a = 0
-24 + 0 + a2 = 0
-24 + a2 = 0

Solving
-24 + a2 = 0

Solving for variable 'a'.

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

Add '24' to each side of the equation.
-24 + 24 + a2 = 0 + 24

Combine like terms: -24 + 24 = 0
0 + a2 = 0 + 24
a2 = 0 + 24

Combine like terms: 0 + 24 = 24
a2 = 24

Simplifying
a2 = 24

Take the square root of each side:
a = {-4.898979486, 4.898979486}