Answer:
When the eqn cuts the x-axis , y=0
3x=12
x=12/3
x=4
So,at x=4 is the point at which the linear equation cuts the x-axis
7 + 1.25t = 43.25 <== ur equation
1.25t = 43.25 - 7
1.25t = 36.25
t = 36.25 / 1.25
t = 29 <== he was jumping for 29 minutes
The second answer is 4 times as small as the first
If the discount is 15 percent, he still pays (100-15) or 85%
125.99 * 85%
125.99 * .85 = 107.09 is the price he pays for the rod
107.09 * .03 =3.21 is the sales tax
107.09+3.21=110.30 is the price of the rod with the discount and the tax