54=(x+2)(5-2x)

Solution for 54=(x+2)(5-2x) equation:

Simplifying
54 = (x + 2)(5 + -2x)

Reorder the terms:
54 = (2 + x)(5 + -2x)

Multiply (2 + x) * (5 + -2x)
54 = (2(5 + -2x) + x(5 + -2x))
54 = ((5 * 2 + -2x * 2) + x(5 + -2x))
54 = ((10 + -4x) + x(5 + -2x))
54 = (10 + -4x + (5 * x + -2x * x))
54 = (10 + -4x + (5x + -2x2))

Combine like terms: -4x + 5x = 1x
54 = (10 + 1x + -2x2)

Solving
54 = 10 + 1x + -2x2

Solving for variable 'x'.

Combine like terms: 54 + -10 = 44
44 + -1x + 2x2 = 10 + 1x + -2x2 + -10 + -1x + 2x2

Reorder the terms:
44 + -1x + 2x2 = 10 + -10 + 1x + -1x + -2x2 + 2x2

Combine like terms: 10 + -10 = 0
44 + -1x + 2x2 = 0 + 1x + -1x + -2x2 + 2x2
44 + -1x + 2x2 = 1x + -1x + -2x2 + 2x2

Combine like terms: 1x + -1x = 0
44 + -1x + 2x2 = 0 + -2x2 + 2x2
44 + -1x + 2x2 = -2x2 + 2x2

Combine like terms: -2x2 + 2x2 = 0
44 + -1x + 2x2 = 0

Begin completing the square.  Divide all terms by
2 the coefficient of the squared term: 

Divide each side by '2'.
22 + -0.5x + x2 = 0

Move the constant term to the right:

Add '-22' to each side of the equation.
22 + -0.5x + -22 + x2 = 0 + -22

Reorder the terms:
22 + -22 + -0.5x + x2 = 0 + -22

Combine like terms: 22 + -22 = 0
0 + -0.5x + x2 = 0 + -22
-0.5x + x2 = 0 + -22

Combine like terms: 0 + -22 = -22
-0.5x + x2 = -22

The x term is -0.5x.  Take half its coefficient (-0.25).
Square it (0.0625) and add it to both sides.

Add '0.0625' to each side of the equation.
-0.5x + 0.0625 + x2 = -22 + 0.0625

Reorder the terms:
0.0625 + -0.5x + x2 = -22 + 0.0625

Combine like terms: -22 + 0.0625 = -21.9375
0.0625 + -0.5x + x2 = -21.9375

Factor a perfect square on the left side:
(x + -0.25)(x + -0.25) = -21.9375

Can't calculate square root of the right side.

The solution to this equation could not be determined.