Question

The area of a rectangular room is given by the trinomial x^2 - 3x - 28. What are the possible dimensions of the rectangle? Use Factoring.
A.(x-6) and (x-5)
B.(x+6) and (x-5)
C.(x+6) and (x+5)
D.(x-6) and (x+5)

Answer 1

Something about the question doesn't make sense... are you sure those are the answer choices?

Answer 2

Because there doesn't seem to be any way to factor x^2 - 3x - 28 into the given choices.

Answer 3

A.(x+7) and (x-4)
B.(x-7) and (x-4)
C.(x+7) and (x+4)
D.(x-7) and (x+4)
these are the correct answer choices @jtvatsim

Answer 4

OK, that makes much more sense.

Answer 5

Can you help?

Answer 6

So how would you start to factor x^2 - 3x - 28? Any ideas?

Answer 7

No, I actually needed help with the entire problem.

Answer 8

OK... Let's start with something easier and work our way up. I will give you a different question to answer first.

Are you able to multiply these two things together: x(x + 1) = ?

Answer 9

1x

Answer 10

OK, and how did you get that?

Answer 11

x*x =x
x+ 1+ 1x

Answer 12

x+1 =1x *

Answer 13

OK, I see what you did. But, we have to remember that x*x = x^2. The exponent tells us how many times we multiplied x., so It's important to keep that there.

Answer 14

So here is what happens: x(x+1) = x*x + x*1 Notice how the left x multiplies both pieces inside. Then, x*x becomes x^2, and x*1 becomes x. So the final answer is x^2 + x.

x(x+1) = x^2 + x.

Does that make sense?

Answer 15

yes, it makes sense

Answer 16

OK, how about this one just to make sure you've got it: x(x + 3) = ?

What would you get for that?

Answer 17

I know this is painful, but it will help us solve the real question we care about. :)

Answer 18

x^2+x3

Answer 19

3x