Answer: The expression is undefined for x=4 and x=5.
The expression is undefined for any x that makes the denominator 0. This leads to solving a quadratic equation:

For these kinds of expressions use FOIL (first, outside, inside, last).
-2x • 9x = -18x^2
-2x • -3y = 6xy
8y • 9x = 72 xy
8y • -3y = -24y^2
Now combine them all:
-18x^2 + 78xy - 24y^2
Answer:
Either 2.4 boxes or 6
Step-by-step explanation:
10% of 40 is 4
60% of 40 is 24
Either 2.4 boxes or 6