Question

If Omar still needs 458How much does he need after saving for 5 weeks

Answer 1

(a) Setting A(w)=458, we get:

`800-18w=458.`

Subtracting 800 from the above equation we get:

`\begin{gathered} 800-18w-800=458-800, \\ -18w=-342. \end{gathered}`

Dividing the above equation by -18 we get:

`\begin{gathered} (-18w)/(-18)=(-342)/(-18), \\ w=19. \end{gathered}`

Therefore Omar has been saving for 19 weeks.

(b) Recall that to evaluate a function at a given value, we substitute the variable by the given value.

Evaluating A(w) at w=5 we get:

`A(5)=800-18\cdot5.`

Simplifying the above result we get:

`\begin{gathered} A(5)=800-90 \\ =710. \end{gathered}`

Answer:

(a) 19.

(b) $710.