a) x = y + 25
y |_____|
x |_____| +25
b) x = y - 30 ⇒ y - 30 = x ⇒ y = x + 30
x |_____|
y |_____| +30
c) x= 3y
y |____|
x |____|____|____|
d) x = y:4 ⇒ y:4 = x ⇒y = 4x
x |____|
y |____|____|____|____|
e) x:y=5 ⇒x = 5y
y |____|
x |____|____|____|____|____|
f) x : y = 2 rest 3 ⇒ x =2y + 3
y |____|
x |____|____| + 3