Hey there!
y + 3 = 30
SUBTRACT 3 to BOTH SIDES
y + 3 - 3 = 30 - 3
CANCEL out: 3 - 3 because that gives you 0
KEEP: 30 - 3 because that gives you the value of y
y = 30 - 3
30 - 3 = y
y = 27
Answer: y = 27
Good luck on your assignment and enjoy your day!
~Amphitrite1040:)