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:
45
Step-by-step explanation:

We can begin by rearranging this into multiplication:

Now we can factor the numerators and denominators:

The factors
(x+4) and
(x+2) cancel out, leaving us with:

Our answer comes out to be:

or

Based on the numerator of the second fraction (since we used its inverse), the denominators of both, and the factors we canceled out earlier, the restrictions are
x ≠ -4, -3, -2, -1, 4
You'd first have to find out what percentage of people would be 30 out of 100%