ANSWER:
Start value b = 0
Rate of change k = 3
Relation: 1:3
STEP-BY-STEP EXPLANATION:
We can calculate rate of change as follows:
[tex]k=\frac{f(x_2)-f(x_1)}{x_2-x_1}[/tex]
We substitute for the points (1,3) and (5,15)
[tex]k=\frac{15-3}{5-1}=\frac{12}{4}=3[/tex]
The starting value b, we calculate it like this:
[tex]\begin{gathered} y=kx+b \\ 15=3\cdot5+b \\ b=15-15 \\ b=0 \end{gathered}[/tex]
Therefore, when x = 49, the value of y would be:
[tex]\begin{gathered} y=3\cdot49+0 \\ y=147 \end{gathered}[/tex]
