Answer:
3a. 84
3b. 150
Step-by-step explanation:
(3*7)+(3*21)
what is 3*7? it's 21
what is 3*21? it's 63
so 21 + 63 is the answer to the first question :D
10*(8+7)
8+7 first cause it's in parentheses
15
10*15 is equal to 150
