Today, jin's age is 1/3 of mary's age. in four years, jin's age will be 1/2 of mary's age. how old is mary today?

a)6 yrs old
b)9yrs old
c)12 yrs old
d) 16yrs old

C)12 Years Old

Step-by-step explanation:

Today, Jin is 4. In four years, Mary will be 16. Jin will be 8. 8=1/2(16)

answer: b.

step-by-step explanation:

the y coordinate for point b is 0, and answer b is the only one with that y coordinate.

x = -3

y = -18

step-by-step explanation:

to solve by substitution, substitute one variable and solve for the other. then substitute again to find the remaining variable.

x-1/3(3x-9) = -3 since y=3x-9 substittute y.

x-1/3(3x-9)=-3

x + x +3 = -3

2x+3=-3

2x+3-3= -3-3

2x=-6

x=-3

substitute again into y=3x-9

y=3(-3)-9

y=-9-9

y=-18