Answer :
To solve this problem we use the two points formula for the equation of a line and solving for y we get:
[tex]\begin{gathered} y-60=\frac{70-60}{5-3}(x-3)\text{.} \\ y-60=\frac{10}{2}(x-3), \\ y=5(x-3)+60, \\ y=5x-15+60, \\ y=5x+45. \end{gathered}[/tex]Answer: y=5x+45.