Simplify the expression 3a(3-a)+3(a^2-3)+3a

3 (4 a - 3)

Step-by-step explanation:

Simplify the following:

3 a (3 - a) + 3 (a^2 - 3) + 3 a

3 a (3 - a) = 9 a - 3 a^2:

9 a - 3 a^2 + 3 (a^2 - 3) + 3 a

3 (a^2 - 3) = 3 a^2 - 9:

3 a^2 - 9 - 3 a^2 + 9 a + 3 a

Grouping like terms, 3 a^2 - 3 a^2 + 9 a + 3 a - 9 = (9 a + 3 a) - 9 + (-3 a^2 + 3 a^2):

(9 a + 3 a) - 9 + (-3 a^2 + 3 a^2)

9 a + 3 a = 12 a:

12 a - 9 + (-3 a^2 + 3 a^2)

3 a^2 - 3 a^2 = 0:

12 a - 9

Factor 3 out of 12 a - 9:

 3 (4 a - 3)

42

step-by-step explanation:

on monday rodney ate 1/4th of the sandwich = 3/12

on tuesday he ate 1/3rd of the sandwich = 4/12

therefore in total he has eaten = 3/12 + 4/12 = 7/12

thus we can say that he has eaten 7/12 of the sandwich on monday and tuesday alltogether.

happy to

pls mark as brainliest.