Answer :
[tex]\begin{gathered} let\text{ y be the number of stick insects and x the w}eeks,then\text{ } \\ y=mx+b \\ is\text{ the linear behavior.} \\ In\text{ this case when y=40 insects we start counting, hence, x=0,Therefore,} \\ 40=m(0)+b \\ \text{hence, b=40. Then the linear equation has the form} \\ y=mx+40 \\ Now.\text{ me must find the slope m. In} \end{gathered}[/tex][tex]\begin{gathered} In\text{ order to find the slope, we can use the given data:} \\ \text{when x=4 w}eeks\text{ then y=75 insects. By substituying these data into the linear equations, one has} \\ 75=m(4)+40 \\ 75=4m+40 \\ 4m=75-40 \\ 4m=35 \\ m=\frac{35}{4} \\ m=8.75 \\ \text{Hence, the linear behavior is given by} \\ y=8.75x\text{ + 40} \end{gathered}[/tex][tex]\begin{gathered} b)\text{ In this case y=350 insects and we must find x. that is} \\ 350=8.75x+40 \\ 350-40=8.75x \\ 8.75x=310 \\ x=\frac{310}{8.75} \\ x=35.429\text{ w}eeks \end{gathered}[/tex][tex]\begin{gathered} c)\text{ the rate of growing is given by the slope. Then, the rate is} \\ m=8.75=\frac{35}{4} \end{gathered}[/tex]