Maria = x
Tom = y
Use substitution
x+y=30
2y=x
2y+y=30
3y=30
y=10
Tom is 10 years old.
x+y=30
x+10=30
x=20
Maria is 20 years old.
Answer:
Step-by-step explanation:

Answer:
(3,12)
Step-by-step explanation:
you would put the 12 as y then 3×3=9+6=15 and 12 doesn't equal 15
Answer:
The vertex of the quadratic function is:

Step-by-step explanation:
Given the function

As the vertex of the form
is defined as:

As the quadratic function of parabola params are

so



Putting
to determine 




Therefore, the vertex of the quadratic function is:

Answer: 12 inches to 1 foot.
Step-by-step explanation: Well, there is 12 inches in 1 foot, so the last one if I'm not mistaken. knowing this, 100 / 12 = 8.33
100 inches per minute converts to 8.33 feet per minute.