y=(x+1)(x+3)(x-4)

Solution for y=(x+1)(x+3)(x-4) equation:

Simplifying
y = (x + 1)(x + 3)(x + -4)

Reorder the terms:
y = (1 + x)(x + 3)(x + -4)

Reorder the terms:
y = (1 + x)(3 + x)(x + -4)

Reorder the terms:
y = (1 + x)(3 + x)(-4 + x)

Multiply (1 + x) * (3 + x)
y = (1(3 + x) + x(3 + x))(-4 + x)
y = ((3 * 1 + x * 1) + x(3 + x))(-4 + x)
y = ((3 + 1x) + x(3 + x))(-4 + x)
y = (3 + 1x + (3 * x + x * x))(-4 + x)
y = (3 + 1x + (3x + x2))(-4 + x)

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

Multiply (3 + 4x + x2) * (-4 + x)
y = (3(-4 + x) + 4x * (-4 + x) + x2(-4 + x))
y = ((-4 * 3 + x * 3) + 4x * (-4 + x) + x2(-4 + x))
y = ((-12 + 3x) + 4x * (-4 + x) + x2(-4 + x))
y = (-12 + 3x + (-4 * 4x + x * 4x) + x2(-4 + x))
y = (-12 + 3x + (-16x + 4x2) + x2(-4 + x))
y = (-12 + 3x + -16x + 4x2 + (-4 * x2 + x * x2))
y = (-12 + 3x + -16x + 4x2 + (-4x2 + x3))

Combine like terms: 3x + -16x = -13x
y = (-12 + -13x + 4x2 + -4x2 + x3)

Combine like terms: 4x2 + -4x2 = 0
y = (-12 + -13x + 0 + x3)
y = (-12 + -13x + x3)

Solving
y = -12 + -13x + x3

Solving for variable 'y'.

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

Simplifying
y = -12 + -13x + x3