Answer: She added 7x and 3y
Step-by-step explanation: The final answer should be 7x + 3y, not 10xy.
Solve first equation for y:
5x+y=10
y=10-5x. Plug this equation into second equation
-x-(10-5x)=-2
-x-10+5x=-2
4x=8
x=2 (plug x into first equation)
5(2)+y=10
y=0
Blank #1 is 0.67 and Blank #2 is 13.3. I am not sure about Blank #3. Here is a tip: Mean absolute deviation is the average of the absolute deviations. Tell me if I am right ok?