Debbie bought x pens. She paid $0.75, including tax, per pen. She gave the cashier $20 and received $8.75 in change. How many pens did Debbie purchase?

15

Step-by-step explanation:

if she gave 20$ and got 8.75$ in change, she payed 11.25$

11.25$ (total) / 0.75 (per pen)= 15 (pens she bought)

1. when "a" is a root of a polynomial, (x -a) is a factor of it. for the three roots given, the factors of the desired polynomial are (x +2)(x -1/2)(x -3).

in order to make the leading coefficient be negative, we need to multiply this product by a negative number. any negative number will do, but we choose a small (magnitude) value that will eliminate the fraction: -2.

then

f(x) = -2(x +2)(x -1/2)(x -3) = -(x +2)(2x -1)(x -3)

= -(2x² +3x -2)(x -3)

= -(2x³ -3x² -11x +6)

f(x) = -2x³ +3x² +11x -6

2. a graph created by the desmos on-line graphing calculator is shown, and the zeros are highlighted.

3. as indicated in part 1, the multiplier of this equation can be anything and the zeros will remain the same. you want a negative leading coefficient, so the "anything" is restricted to any of the infinite number of numbers that will make that be the case.

where is the graph, sweetheart?

step-by-step explanation: