7. 11, 12, 5, 3, x; mean 7.4

x=6

Step-by-step explanation:

Mean is another word for average. It is found by adding up all of the values, and dividing that number by the amount of values you added together.

You have 5 values that get a mean or, average, of 7.4

1) We can write this as the following:

(11+12+5+3+x) / 5=7.4

2) To solve, multiply both sides by 5:

11+12+5+3+x=37

3) Now combine all of the numbers on the left:

31+x=37

4) Now subtract 31 from both sides:

x=6

6.4

Step-by-step explanation:

Multiply 7.4 x 6

them subtract all numbers from it and you end up with 6.4