f(x)=(x+2)(x+1)

Solution for f(x)=(x+2)(x+1) equation:

Simplifying
f(x) = (x + 2)(x + 1)

Multiply f * x
fx = (x + 2)(x + 1)

Reorder the terms:
fx = (2 + x)(x + 1)

Reorder the terms:
fx = (2 + x)(1 + x)

Multiply (2 + x) * (1 + x)
fx = (2(1 + x) + x(1 + x))
fx = ((1 * 2 + x * 2) + x(1 + x))
fx = ((2 + 2x) + x(1 + x))
fx = (2 + 2x + (1 * x + x * x))
fx = (2 + 2x + (1x + x2))

Combine like terms: 2x + 1x = 3x
fx = (2 + 3x + x2)

Solving
fx = 2 + 3x + x2

Solving for variable 'f'.

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

Divide each side by 'x'.
f = 2x-1 + 3 + x

Simplifying
f = 2x-1 + 3 + x

Reorder the terms:
f = 3 + 2x-1 + x