Answer:
999
Step-by-step explanation:
this is the answer but I don't sure.
Just plug in 4 for the x
2*4 +4y =36
8+4y =36
4y =36-8
4y=28
y= 28/4
y=7
Answer:
500 times
Step-by-step explanation:
They breathe 20 times per minute for 25 minutes
20(times per minute) x 25(minutes) = 500
For this case we have the following system of two equations with two unknowns:

Adding both equations we have to eliminate the variable "x":

Adding common terms, keeping in mind that different signs are subtracted and the sign of the major is placed:

Answer:

Option A