^{2}

^{2}- 4x = 165

^{2}- 4x - 165 = 0

^{2}+ 165*4 = 676

this is quadratic word problems

Tutors, sign in to answer this question.

side - x

area - x^{2}

perimeter - 4x

x^{2} - 4x = 165

x^{2} - 4x - 165 = 0

D = (-4)^{2} + 165*4 = 676

x1 = (4 + 26) / 2 = 15

x2 = (4 - 26) / 2 = -11

Disregard x2 since it is negative

Answer is : side of the square is 15cm.

Hey Raven -- an intuitive approach ... perimeter 4d must be an even # ...

area d*d seems to be an odd multiple of 5 to produce an "offset" of 165 ... 5x5 too small

... try 15x15 ==> 225 minus 60 is 165 ==> **d= 15cm** ... Best regards :)

Hi Raven;

perimeter=4x

area=x^{2}

x^{2}=4x+165

x^{2}-4x-165=0

For the FOIL...

FIRST must be (x)(x)=x^{2}

OUTER and INNER must add-up to -4x.

LAST must be (11)(15) or (15)(11) and one number must be negative to render the product of -165.

(x+11)(x-15)=0

Let's FOIL...

FIRST...(x)(x)=x^{2}

OUTER...(x)(-15)=-15x

INNER...(11)(x)=11x

LAST...(11)(-15)=-165

x^{2}-15x+11x-165=0

x^{2}-4x-165=0

(x+11)(x-15)=0

Either parenthetical equation must equal zero...

x+11=0

x=-11--not applicable. Measurements cannot be negative.

x-15=0

Let's check our work...

x^{2}=4x+165

(15)^{2}=[(4)(15)]+165

225=60+165

225=225

Tom D. | Very patient Math Expert who likes to teachVery patient Math Expert who likes to te...

I don't like the way this question is phrased because it is mixing an area (cm^2) with the linear dimension of perimeter (cm). That is never good practice. We'll assume the question addresses the magnitude of the area (cm^2) with the perimeter (cm).

s^2 = 4s + 165

s^2 - 4s - 165 =0

(S+11)(S-15) =0 --->S=15 cm

Already have an account? Log in

By signing up, I agree to Wyzant’s terms of use and privacy policy.

Or

To present the tutors that are the best fit for you, we’ll need your ZIP code.

Your Facebook email address is associated with a Wyzant tutor account. Please use a different email address to create a new student account.

Good news! It looks like you already have an account registered with the email address **you provided**.

It looks like this is your first time here. Welcome!

To present the tutors that are the best fit for you, we’ll need your ZIP code.

Please try again, our system had a problem processing your request.

Alexis G.

All-Subject/Test Prep Tutor, Specializing in Language Instruction

$11.25 per 15 min

View Profile >

Michael B.

Effective Tutor Specializing in Mathematics

$10 per 15 min

View Profile >

Haroldo S.

Biomedical Engineer (UC Berkeley PhD) for Math and Science Tutoring

$12.50 per 15 min

View Profile >