Factor the greatest common factor.
-30k^6 + 9k^5 - 21k^4

Since both terms are perfect squares, factor using the difference of squares formula,  

a

2

−

b

2

=

(

a

+

b

)

(

a

−

b

)

where  

a

=

k

2

and  

b

=

1

.

9

(

−

36

k

6

+

k

5

−

k

−

2

)

step-by-step explanation:

you divide the denominator by the numerator on both sides and if the quotients are equal then the fractions are equivalent

x is the total time in minutes for the free response

you are given number of questions as 15 - m and time per item as 8 minutes

to find x multiply the two givens together:

x = 8 * (15-m) = 8(15-m)