=(2-a)(4-a)

Solution for =(2-a)(4-a) equation:

Simplifying
0 = (2 + -1a)(4 + -1a)

Multiply (2 + -1a) * (4 + -1a)
0 = (2(4 + -1a) + -1a * (4 + -1a))
0 = ((4 * 2 + -1a * 2) + -1a * (4 + -1a))
0 = ((8 + -2a) + -1a * (4 + -1a))
0 = (8 + -2a + (4 * -1a + -1a * -1a))
0 = (8 + -2a + (-4a + 1a2))

Combine like terms: -2a + -4a = -6a
0 = (8 + -6a + 1a2)

Solving
0 = 8 + -6a + 1a2

Solving for variable 'a'.

Combine like terms: 0 + -8 = -8
-8 + 6a + -1a2 = 8 + -6a + 1a2 + -8 + 6a + -1a2

Reorder the terms:
-8 + 6a + -1a2 = 8 + -8 + -6a + 6a + 1a2 + -1a2

Combine like terms: 8 + -8 = 0
-8 + 6a + -1a2 = 0 + -6a + 6a + 1a2 + -1a2
-8 + 6a + -1a2 = -6a + 6a + 1a2 + -1a2

Combine like terms: -6a + 6a = 0
-8 + 6a + -1a2 = 0 + 1a2 + -1a2
-8 + 6a + -1a2 = 1a2 + -1a2

Combine like terms: 1a2 + -1a2 = 0
-8 + 6a + -1a2 = 0

Factor a trinomial.
(-4 + a)(2 + -1a) = 0

Subproblem 1
Set the factor '(-4 + a)' equal to zero and attempt to solve:

Simplifying
-4 + a = 0

Solving
-4 + a = 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 + a = 0 + 4

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

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

Simplifying
a = 4
Subproblem 2
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
Solution
a = {4, 2}