John is twice as old as Mary. The sum of their ages is 21. How old is Mary? Let J = John's age and M = Mary's age. Select the system equations that represents the problem.

J = M + 2
M - 2J = 0
J + M = 21
J - 2M = 0

Mary is 7

Because 14+7 =21

So j+m=21

J - 2m= 0

answer: a) (0,0), (1,1), (2,8), and (3,27).

step-by-step explanation:

0^3=0

1^3=1

2^3=8

3^3=27

in effect, the exponential equation for this would me y=3^x. each x-coordinate cubed is giving the y coordinate, so a is your answer : )

what do u need to know

step-by-step explanation: