Determine the resulting polynomial:

f, of, x, equals, 8, x, minus, 2
f(x)=8x−2
g, of, x, equals, minus, 10, x, squared, minus, x, minus, 7
g(x)=−10x
2
−x−7
Find: , f, of, x, dot, g, of, x
Find: f(x)⋅g(x)

1 answer

To find the resulting polynomial \( f(x) \cdot g(x) \) where:

  • \( f(x) = 8x - 2 \)
  • \( g(x) = -10x^2 - x - 7 \)

we will multiply these two polynomials:

\[ f(x) \cdot g(x) = (8x - 2)(-10x^2 - x - 7) \]

Now we will distribute \( f(x) \) over \( g(x) \):

  1. Multiply \( 8x \) by each term in \( g(x) \):

    • \( 8x \cdot (-10x^2) = -80x^3 \)
    • \( 8x \cdot (-x) = -8x^2 \)
    • \( 8x \cdot (-7) = -56x \)
  2. Multiply \( -2 \) by each term in \( g(x) \):

    • \( -2 \cdot (-10x^2) = 20x^2 \)
    • \( -2 \cdot (-x) = 2x \)
    • \( -2 \cdot (-7) = 14 \)

Now we combine all these results together:

\[ f(x) \cdot g(x) = -80x^3 + (-8x^2) + (-56x) + 20x^2 + 2x + 14 \]

Next, we can simplify by combining like terms:

  1. For the \( x^2 \) terms:

    • \( -8x^2 + 20x^2 = 12x^2 \)
  2. For the \( x \) terms:

    • \( -56x + 2x = -54x \)

Putting it all back together, we have:

\[ f(x) \cdot g(x) = -80x^3 + 12x^2 - 54x + 14 \]

Thus, the resulting polynomial \( f(x) \cdot g(x) \) is:

\[ \boxed{-80x^3 + 12x^2 - 54x + 14} \]