We can simply add the expression to simplify the expression. So,
(7+3i)+(-8+9i) =7 +3i -8+9i Get rid of paranthesis.
=(7-8)+(3i+9i) Group the like terms.
= -1 + 12i
If 6 cans of soup cost $1.50
9 cans cost .......................x?
x = 9 * 1.50 / 6
x = 2.25
Answer
9 cans cost $2.25