Answer :
Solution
- We are given the two functions below:
[tex]\begin{gathered} u(x)=4x-2 \\ \\ w(x)=-5x+3 \end{gathered}[/tex]- We are asked to find u(w(-3)).
- In order to find u(w(-3)), we need to first find u(w(x)) and then we can substitute x = -3.
- Since we have been given u(x), then, it means that we can find u(w) as follows:
[tex]\begin{gathered} u(x)=4x-2 \\ u(w),\text{ can be gotten by substituting w for x} \\ \\ u(w)=4w-2 \end{gathered}[/tex]- But we have an expression for w in terms of x. This means that we can say:
[tex]\begin{gathered} u(w)=4w-2 \\ \\ w(x)=-5x+3 \\ \\ \therefore u(w(x))=4(-5x+3)-2 \\ \\ u(w(x))=-20x+12-2 \\ \\ \therefore u(w(x))=-20x+10 \end{gathered}[/tex]- Now that we have an expression for u(w(x)), we can proceed to find u(w(-3)) as follows:
[tex]\begin{gathered} u(w(x))=-20x+10 \\ put\text{ }x=-3 \\ \\ u(w(-3))=-20(-3)+10 \\ \\ u(w(-3))=60+10=70 \end{gathered}[/tex]Final Answer
The answer is
[tex]u(w(-3))=70[/tex]