Question

Which expression is undefined?

Answer 1

D. 15/9+(-9) really just means 15/9-9
Hence, 15/0
You cannot divide by 0 so you get an undefined answer

Answer 2

Answer:

D

Step-by-step explanation:

If the denominator ( bottom number ) is 0 then the expression is undefined. This is simply because a number cannot be divided by 0. However 0 can be divided by a number, the quotient would just end up being 0 though. This means that the numerator ( top number ) can be 0 and the expression will be defined

A. 0 / 3 = 0

0 is a defined answer so A cannot be the answer

B. $\frac{0-8}{-4} =\frac{-8}{-4} =2$

2 is a defined number so B cannot be the answer.

C $\frac{7-7}{9} =\frac{0}{9} =0$

0 is a defined number so C cannot be the answer

D $\frac{15}{9+(-9)} =\frac{15}{0} =$ undefined

Because 15 is being divided by 0 and no number can truly be divided by 0 the quotient is undefined therefore D is the answer