Answer:
The answer is C!!
Step-by-step explanation:
Let

be the amount of time it takes to perform an arm routine and

be the amount of time it takes to perform an abdominal routine. We see:


Subtracting the second equation from the first gives

. Substituting gives

, so

and

.
Thus, an arm routine takes ten minutes and an abdominal routine takes thirty minutes.
Answer:
(2,-1)
Step-by-step explanation:
Multiply first equation by 2:
10x + 2y = 18
Subtract the second equation from this so that the 2y terms cancel:
10x - 3x = 18 - 4
7x = 14
x = 2
Plug into first equation to find y:
5(2) + y = 9
10 + y = 9
y = -1
The answer is (2,-1)
Answer:
500
Step-by-step explanation:
multiply all of them