Mia and holly can clean their room in 20 minutes, working together. Working alone, mia can clean the room in 30. How long would it take holly to clean alone?

 Holly would take 60 minutes to clean alone.

Step-by-step explanation:

Let t = Time taken by Holly to clean alone.

Given: Time taken by Mia to clean alone = 30 minutes

Time taken by Mia and holly to clean their room = 20 minutes

Then,

Hence, Holly would take 60 minutes to clean alone.

the correct option is:

b. a value of the variable that makes the polynomial equal to zero.

the root or roots of a polynomial are the values of the variable that makes the polynomial equal to 0. we can find the roots of a polynomial making the expression equal to 0 and then, isolating the variable (it it has just one variable).

for example, given the following polynomial:

the root or zero of the polynomial, can be found by making the expression equal to 0, and then, isolating the variable, so, finding the root we have:

therefore, we have that the root of the polynomial is equal to 2.

we must remember that the number of roots that a polynomial can have, will depend on the degree of the polynomial, a first degree polynomial have will have one single root, a second degree polynomial (quadratic expression) may have two roots and so.

hence the correct option is:

b. a value of the variable that makes the polynomial equal to zero.

have a nice day!