Answer:
a) Graphing the function we have;
Therefore, the amount he saves after 5 weeks is $120
b) The relationship is not proportional because the corresponding values are not proportional and do not pass through the origin.
Explanation:
Given the data in the table.
We can extrapolate to derive the Amount saved in the following weeks;
[tex]\begin{gathered} 0\rightarrow70 \\ 1\rightarrow80 \\ 2\rightarrow90 \\ 3\rightarrow100 \\ 4\rightarrow110 \\ 5\rightarrow120 \end{gathered}[/tex]
Graphing the function we have;
Therefore, the amount he saves after 5 weeks is $120
To determine if the relationship is proportional or not.
For it to the proportional;
[tex]\frac{y_1}{x_1}=\frac{y_2}{x_2}=\frac{y_3}{x_3}[/tex]
substituting the values from the table or graph, we have;
[tex]\begin{gathered} \frac{y_1}{x_1}=\frac{80}{1} \\ \frac{y_2}{x_2}=\frac{90}{2} \\ \frac{y_3}{x_3}=\frac{100}{3} \\ \frac{80}{1}\ne\frac{90}{2}\ne\frac{100}{3} \end{gathered}[/tex]
Therefore, the relationship is not proportional because the corresponding values are not proportional and do not pass through the origin.