Answer:
Natalie: 12
Fred: 24
Step-by-step explanation:
x= natalie
y= fred
x+y=36
y+4x=72
Let's start by isolating a variable
x+y=36
x-36= -y
-x+36=y
(we do this step because it's important that the y is a negative)
We can plug this into the second equation
-x+36+4x=72
solve for x
3x=36
x=12
Plug in this x value into any of the two beginning equations
12+y=36
y=24
