X=quarters, y=dimes
7+2x=y
0.25x+0.1y=10.15
we substitute the first equation into the second equation
0.25x+0.1(7+2x)=10.15
0.25x+0.7+0.2x=10.15
0.45x+0.7-0.7=10.15-0.7
0.45x=9.45
0.45x/0.45=9.45/0.45
x=21 quarters
7+2x=y, x=21
7+2(21)=y
7+42=y
y=49 dimes
check: 0.25x+0.1y=10.15 when x=21, y=49
21(0.25)=5.25 in quarters
49(0.1)=4.90 in dimes
5.25+4.90=10.15
Answer:
See the explanation
Step-by-step explanation:
Given function

We need to find
value corresponding to each
value.
So, plug each
value in equation we get,

Now in next part of question it ask us to check each ordered pair.
Let us plug each
value and
value in the function 

we can see ordered pair
true for function 
D.2y+3 i think is the answer
The answer is 21, 21 is the value of x