Four expressions are shown below:

a: 21x + 6
b: 3(7x + 2)
c: 18x + 9
d: 3(6x + 3)

which two expressions are equivalent to 3(6x + 2 + x)?

a and d
c and d
a and b
b and c

answer: the answer is 127 degrees

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 -