Answer: I will give you a answer for both of them.
Step-by-step explanation:
First equation: x+y=20
1. Subtract y from both sides.
x=20−y
Second equation: 2x+y=25
1. Subtract y from both sides.
2x=25−y
2. Divide both sides by 2.
[tex]X[/tex][tex]=[/tex][tex]\frac{25-y}{2}[/tex]