Answer:
Follows are the solution to this question:
Step-by-step explanation:
In this question, we apply the associative property that calculates the given value, which can be defined as follows:
Rule:

Let,

put the value in the above rule:
Solve L.H.S part:

Solve R.H.S part:

So, L.H.S=R.H.S
Answer:
i got 21.42 (rounded to the nearest second decimal) if not my full answer was 21.42147412. sorry if its incorrect
Step-by-step explanation:
20x+ 5y = 15
Move 20x to the other side. Sign changes from +20x to -20x
20x-20x+5y=-20x+15
5y=-20x+15
Divide both sides by 5
5y/5=y ( Cross out 5 and 5, divide by 5, 1*1*y=y)
-20/5=-4x
15/5=3
y=-4x+3 or y=3-4x
Answer: y=-4x+3 or y=3-4x
Do you have notes that you could share with me? Then maybe I could manage to help out more