You would multiply the orignial price by (10%) converted to decimal to find the discount:
21 * 0.10
=2.10
Then, you subract the discount from the original price to see how much he paid:
21 - 2.10 = $18.90
B.) Making Change
Hope this helps!!
Answer:
8x+5005073
Step-by-step explanation:
Answer:
{x|-4, -1 ≠ x}
Step-by-step explanation:

Find two numbers that when added up to 5, they also multiply up to 4. Then set them equal to zero to get your roots. Those are the numbers that we want to stay away from because those will make the denominator result in 0, and nothing can be EVER divided by zero.
I hope this helps you out alot, and as always, I am joyous to assist anyone at any time.