Expanding:


Reorder the terms:
f(x) = 0.05(2 + x)(x + -3)(x + 5)

Reorder the terms:
f(x) = 0.05(2 + x)(-3 + x)(x + 5)

Reorder the terms:
f(x) = 0.05(2 + x)(-3 + x)(5 + x)

Multiply (2 + x) * (-3 + x)
f(x) = 0.05(2(-3 + x) + x(-3 + x))(5 + x)
f(x) = 0.05((-3 * 2 + x * 2) + x(-3 + x))(5 + x)
f(x) = 0.05((-6 + 2x) + x(-3 + x))(5 + x)
f(x) = 0.05(-6 + 2x + (-3 * x + x * x))(5 + x)
f(x) = 0.05(-6 + 2x + (-3x + x2))(5 + x)

Combine like terms: 2x + -3x = -1x
f(x) = 0.05(-6 + -1x + x2)(5 + x)

Multiply (-6 + -1x + x2) * (5 + x)
f(x) = 0.05(-6(5 + x) + -1x * (5 + x) + x2(5 + x))
f(x) = 0.05((5 * -6 + x * -6) + -1x * (5 + x) + x2(5 + x))
f(x) = 0.05((-30 + -6x) + -1x * (5 + x) + x2(5 + x))
f(x) = 0.05(-30 + -6x + (5 * -1x + x * -1x) + x2(5 + x))
f(x) = 0.05(-30 + -6x + (-5x + -1x2) + x2(5 + x))
f(x) = 0.05(-30 + -6x + -5x + -1x2 + (5 * x2 + x * x2))
f(x) = 0.05(-30 + -6x + -5x + -1x2 + (5x2 + x3))

Combine like terms: -6x + -5x = -11x
f(x) = 0.05(-30 + -11x + -1x2 + 5x2 + x3)

Combine like terms: -1x2 + 5x2 = 4x2
f(x) = 0.05(-30 + -11x + 4x2 + x3)
f(x) = (-30 * 0.05 + -11x * 0.05 + 4x2 * 0.05 + x3 * 0.05)
f(x) = (-1.5 + -0.55x + 0.2x2 + 0.05x3)