y=(x-4)(x+1)

Solution for y=(x-4)(x+1) equation:

Simplifying
y = (x + -4)(x + 1)

Reorder the terms:
y = (-4 + x)(x + 1)

Reorder the terms:
y = (-4 + x)(1 + x)

Multiply (-4 + x) * (1 + x)
y = (-4(1 + x) + x(1 + x))
y = ((1 * -4 + x * -4) + x(1 + x))
y = ((-4 + -4x) + x(1 + x))
y = (-4 + -4x + (1 * x + x * x))
y = (-4 + -4x + (1x + x2))

Combine like terms: -4x + 1x = -3x
y = (-4 + -3x + x2)

Solving
y = -4 + -3x + x2

Solving for variable 'y'.

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

Simplifying
y = -4 + -3x + x2