What are the factor of 80k^2_45

80k^2 - 45

= 5(16k^2 - 9), factoring out the GCF of the two terms, which is 5.

= 5(4k+3)(4k-3), since 16k^2 - 9 can be represented by the difference of two squares (4k)^2 - 3^2

What are the factor of 80k^2_45

Tutors, please sign in to answer this question.

80k^2 - 45

= 5(16k^2 - 9), factoring out the GCF of the two terms, which is 5.

= 5(4k+3)(4k-3), since 16k^2 - 9 can be represented by the difference of two squares (4k)^2 - 3^2

Not sure i'm reading this correctly, but assuming the expression is:

80K^{2} - 45 then use the quadratic formula to get the roots. (-b
+ sqrt(b^{2}-4ac)/2a = formula

where a,b,c are the coefficients of the first,second,third term.

NOTE: there is NO 'b' term, just a = 80 and c = 45

so we have 0 + sqrt(0^{2 }- 4(80)(-45)) all divided by 160

thus we have 0 + sqrt(1440) all divided by 160.

remember: the sqrt(1440) = sqrt(144) times sqrt(100), so we have 12 times 10

thus we have +(120)/160

Now we have TWO roots. .75 and -.75

so.......

the factors of the expression are (k+.75) and (k-.75)

there are other ways to do this as well by just factoring, but use of the quadratic is easier to see.

Dina K.

Patient, Fun and Engaging Tutor!

Staten Island, NY

5.0
(22 ratings)

Yang Z.

Chemistry, Biology, Table Tennis and Volleyball Mentor

Brooklyn, NY

4.5
(2 ratings)

Donald P.

Exceptional Math and Literacy Tutor

New York, NY

## Comments

Stuart,

I agree that the solutions are .75 and -.75 if we were trying to solve an equation; however, this is an expression and the student is being asked to factor it. Robert is definitely correct. The answer is 5(4k +3)(4k - 3), because it is completely broken down to its smallest factors using only integers.

Sincerely,

Phillip H, NBCT