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 represent the problem.

J = 2M

J + M = 21

Step-by-step explanation:

M = Mary's age

J = John's age

"John is twice as old as Mary."

J = 2M

"The sum of their ages is 21."

J + M = 21

The system of equations is:

J = 2M

J + M = 21

14

step-by-step explanation:

for this pair of functions g(x)=x-2 and f(x)=|x| is (g o f)(a)= |a| -2

step-by-step explanation:

g(x)=x-2

f(x)=|x|

(g o f)(a)=?

(g o f)(x)=g(f(x))

(g o f)(x)=g(|x|)

(g o f)(x)=|x|-2

(g o f)(a)=|a|-2