Which number is not in scientific notation? URGENT! BRAINLIEST WILL BE GIVEN 1) 11 . 10^21
2) 5.7 . 10^9
3) 3.1 . 10^-12
4) 1.67 . 10^-5

1) 11 x 10^21

Step-by-step explanation:

Scientific notation must be in the form

a  x 10^b

Where a is an number between 1 and 10

Clearly the 1st one is above 10 so it goes against the rule of scientific notation

29 is the correct answer

step-by-step explanation:

see explanation

step-by-step explanation:

a

(6r + 7) + (13 + 7r) ( remove brackets and collect like terms )

= 6r + 7 + 13 + 7r

= 13r + 20

b

remove brackets and collect like terms

13 - r - 1 + r

= 12 - r

c

remove brackets and collect like terms

= - 8 - r + 2r - 4

= - 12 + r

d

remove brackets and collect like terms

= 7r - - - 6r

[-   - = - - = - ]

= r -