Question

If the arithmetic mean of 4x, 3x, and 12 is 18, then what is the value of x?

Answer 1

4x+3x+12= 18
7x+12=18
7x=6
x=6/7

So the answer for x is 6/7

Answer 2

Answer:

x = 6

Step-by-step explanation:

When we find the average, we need to add up all the values and divide the answer by the number of values.

We can use this idea as a formula to answer the question:

(4x + 3x + 12) /3 = 18

collect like terms:

(7x + 12) / 3 = 18

Get rid of the fraction:

7x + 12 = 18 x 3 (multiply both sides by 3)

7x + 12 = 54

move x to one side:

7x = 54 - 12 (to do this we subtract 12 from both sides)

7x = 42

x = 42/7  (divide both sides by 7)

x = 6

Hope this helps,

Cate