If a = 3, b = – 1 and c = 2, then a + b + c
a) 5
b) – 5
c) 4
d) – 4
The expression (3c – 3d) – (c – 3d) when simplified is
a) 2c – 6d
b) 2c
c) 4c – 6d
d) 4c