111,764 views
25 votes
25 votes
Express your answer as a polynomial in standard form.

f(x) = -5x + 14
g(x) = x2 + 6x – 7
Find: f(g(x))

User NullReference
by
2.8k points

1 Answer

20 votes
20 votes

Answer:

f(g(x)) = -5x^2 - 30x + 49

Explanation:

f(g(x)) is a composite function, where 'x' in f(x) is replaced by 'x^2 + 6x - 7' because the latter expression is now the input to f(x).

Write out f(x) = -5x + 14, and then replace each 'x' with '( )'

f( ) = -5( ) + 14

Now insert 'g(x)' into the first set of parentheses and 'x^2 + 6x - 7' into the second set of parentheses:

f( ) = -5( ) + 14 becomes:

f(g(x) = -5(x^2 + 6x - 7) + 14. After simpification, this becomes

f(g(x)) = -5x^2 - 30x + 35 + 14, or

f(g(x)) = -5x^2 - 30x + 49

User Turushan
by
3.1k points
Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.