what are the dimensions of the rectangle below if the area is 100ft^2??

Question

anonymous · Answer

@hartnn help!!!!!!!!

tkhunny · Answer

x * (x-15) = 100 where x > 0

anonymous · Answer

So you mean that x^2-15x would be the answer right?

anonymous · Answer

For the simpliefied expression that represents the perimeter of the rectangle right?

anonymous · Answer

@hartnn ?

anonymous · Answer

@Mertsj ?

anonymous · Answer

I need helped bit time!!!! i have a paper to do & this is the only problem that i need!

anonymous · Answer

@electrokid ?

mertsj · Answer

Get it equal to 0 and factor it.

mertsj · Answer

x^2-15x-100=0

anonymous · Answer

So would it be x^2-15x=0 right then it would be x^2-15x-0 right?

anonymous · Answer

wait nevermind so then what 2 number could give 100 & 15?0_o i got 25 & 4 but that wont give me 15

mertsj · Answer

$$x^2-15x-100=(x-20)(x+5)$$

anonymous · Answer

so the expression that represents the perimeter of the rectangle is that right? & then for the leght would be 20 for x & for the width it would be 5 right?

anonymous · Answer

@Mertsj ?

anonymous · Answer

@electrokid ?

anonymous · Answer

Is it good?

mertsj · Answer

Did you set each of those factors to 0?

anonymous · Answer

Nope. wait but its +20 & -5 right?

mertsj · Answer

And would -5 be appropriate for the side of a rectangle?

anonymous · Answer

i dont think so because its negative & i suppose to be positive & the area is positive so no?

mertsj · Answer

So x = 20 and the other side of the rectangle is x-15.

anonymous · Answer

so the width is 20 & the lenght is 5 right?

mertsj · Answer

I believe we would say the length is 20 and the width is 5.  That is customary.

anonymous · Answer

wait so whats the simplified expression that represents the perimeter of the rectangle? was it x^2-15x-100?

anonymous · Answer

@Mertsj?

mertsj · Answer

How do you find perimeter?

anonymous · Answer

by adding but the question wants it in a simplifies form though so would it be 2x+2(x-15)?

mertsj · Answer

That is the expression but it is not simplified.  Use the distributive property and add the like terms

anonymous · Answer

so would it be 2x+ 2x(1-15)? OR! 2X(1-15)?

mertsj · Answer

What is 2(x-15)

anonymous · Answer

The lenght

mertsj · Answer

Have you ever heard of the distributive property?

anonymous · Answer

i originally had x^2-15x but i dont know if thats right though?

mertsj · Answer

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