1 is the answer to nthis/...
9 * 20 = 180
24 has 4 more than that, so multiply 9 to 4 and add it to 180.
9 * 4 = 36
180 + 36 = 216
So 9 * 24 = 216
Answer is A
The binomial can be factored using the difference of squares formula a2-b2 = (a+b) (a-b) where a=x and b=9
(X+9) x(x-9)
Since we have a negative on the outside of the parenthesis, we can just say that this is -1. So now we have -1(-x + 1). when multiply a negative by a negative it cancels out into a positive. and multiplying a negative with a positive will give you a negative. So now we have x - 1.