Question

The area of a rectangular swimming pool is 10x2 – 19x – 15. The length of the pool is 5x + 3. What is the width of the pool?
2x – 18
2x – 5
5x – 5
5x – 22

Answer 1

Area is length times width. So if length is 5x+3 you have to multiply that by something that gives you 10x^2-19x-15. Can you figure it out now?

Answer 2

no, i dont understand this stuff.

Answer 3

You have to multiply 5x+3 by one of those possible answers to get the area, which is 10x^2-19x-15. Do you know how to use the FOIL method? Try multiplying 5x+3 by 2x-18 and 2x-5. One of those is the answer.

Answer 4

ive heard of the foil method but im not sure how to use it.

Answer 5

Ok, let's do 5x+3 * 2x-5. Foil stands for First, Outside, Inside, Last. First term times first term is 5x*2x = 10x^2.

Outside terms: 5x*-5= -25x

Inside terms 3*2x = 6x

Last terms 3*-5=-15

whole thing is 10x^2-25x+6x-15 which simplifies to the given area. So the answer is 2x-5. Understand?

Answer 6

oh yeah, you have to do it that way. thanks i remember the foil method now!

Answer 7

yw

Answer 8

Keep it up!