What effect will multiplying by 3 have on f(x)?

For a positive value k, the graph of y=kf(x) is obtained from the graph of y=f(x) by scaling in the vertical direction. In coordinates, if (x0,y0) is on the graph of y=f(x), then that point moves to (x0,ky0) on the graph of y=kf(x). Any point on the x-axis remains fixed (as then y=0). When k>1, the graph is stretched vertically (away from the x-axis), while if 0<k<1, the graph is compressed vertically (toward the x-axis).

Another way to think about this: The graph of y=kf(x) is exactly the same as the graph of y=f(x) if the y-axis is scaled so that 1 is relabeled k, 2↦2k, −1↦−k, etc.

Step-by-step explanation:

the answer is 31.27mph