Answer:
(12,33)
Step-by-step explanation:
This system can be solved using the substitution method. This is where you replace one variable by another.
Step 1:
Plug in [tex]x+21[/tex] for the y
Step 2:
Combine like terms
[tex]2x+x+21=57\\3x+21=57[/tex]
Step 3:
Subtract 21 from both sides
[tex]3x=36[/tex]
Step 4:
Divide both sides by 3
[tex]x=12[/tex]
Step 5:
Use the first equation and plug in 12 for x
[tex]y=12+21[/tex]
[tex]y=33[/tex]
Step 6:
Proof of work
[tex]2(12)+33=57\\24+33=57\\57=57[/tex]