Question 528220
x+3=5...........(1)
x=3-3y..........(2)

Take (1)
x+3=5...........(1)
x=5-3
x=2
Put the value of x in (2)
x=3-3y..........(2)
2=3-3y
2-3=-3y
-1=-3y
-1/-3=-3y/-3
1/3=y
y=1/3

x,y = 2,1/3

Check
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Put the value of x and y in (2)
x=3-3y..........(2)
2=3-3(1/3)
2=3-(3/3)
2=3-1
2=2