Answer
y=14x + 150
Work Step by Step
We can treat the quantity of shirts as j and the price of them as y, so our two points will be (15,360) and (25,500).
Using $\frac{y_{2}-y_{1}}{x_{2}-x_{1}}$ to find the slope, we get m= $\frac{500-360}{25-15}$ = $\frac{140}{10}$ = $14$
Now, using y=mx+b:
y=14x + b
500=14(25)+b
500=350+b
150=b
y=14x + 150
