Which of these does not exist?

A

√25

B

−√25

C

√−25

D

they all exist

1 / 10

Which of these does not exist?

A

√25

B

−√25

C

√−25

D

they all exist

Write as short as possible

y=3√x−6√2+6√x−2√2

A

y=9√x−4√2

B

y=9√x−8√2

C

y=−3√x+4√2

D

Cannot be written any shorter.

Calculate without a calculator

(√7)2=

Which exercises/theories should I discuss on the board?