Step-by-step explanation:
Step 1: Set y to 5x in the first equation
[tex]x + y = 18[/tex]
[tex]x + (5x) = 18[/tex]
[tex]6x = 18[/tex]
[tex]6x / 6 = 18 / 6[/tex]
[tex]x = 3[/tex]
Step 2: Set x to 3 in the second equation
[tex]y = 5x[/tex]
[tex]y = 5(3)[/tex]
[tex]y = 15[/tex]
Answer: [tex](3, 15)[/tex]
