Answer:
Step-by-step explanation:
8x + 12 = 3x + 5x + 12
8x + 12 = 8x + 12
Bringing like terms on one side
8x - 8x = 12 - 12
x = 0
Answer:
B=-2+5 collecting like terms
B=3 answer
Answer: The average was 9 years old find the average age of both groups is 10 years old.
Step-by-step explanation:
Formula foe average : 
Given : The first group of students consists of 10 and their average age was 13 years old.
i.e.
(1)
The next group consisted of 30 students and their average was 9 years old.
i.e.
(2)
Then from (1) and (2) , the sum of both groups (first group and next group )students = 130+270 =400
Combined students of both groups (first and next group )= 10+30=40
Now , the average of both groups =

Hence, the average was 9 years old find the average age of both groups is 10 years old.
Answer:its easy it the first one you had posted
Step-by-step explanation:
200 +5(200) = 1200 mochas a week in total
They sold 1000 iced mocha in a week
200 x 4=800 hot mochas in 4 weeks
1000 x 4=4000 iced mochas in 4 weeks
They sold 4000-800= 3200 more iced mochas in 4 weeks