Five years ago, John’s age was half of the age he will be in 8 years. How old is he now?

18

Step-by-step explanation:

x-5=(x+8)/2

x-5=x/2+4

add 5

x=x/2+9

subtract x/2

x/2=9

times 2

x=18

step-by-step explanation:

through just a quick inspection, one can see that the graph of this cubing function starts in quadrant iii and ends in quadrant i.   when x = 0, y = 3, so the y-intercept is (0, 3).

if graphs are part of the problem statement, share them.   .