Question

Write and solve an equation to find the value of the variable 104, 137, 154, 131, x; meaan=130

Answer 1

X = 124. Since the mean (average) is calculated by adding all the sums up, then
one divides by the quantity of numbers that are present. So take the mean multiple by the number 5, which is the quantity of numbers present. You get 650 then subtract 104, 137, 154, and 131 and your left with the numeric value of x being 124.

Answer 2

When you want to know the mean of $n$ quantities, denoted by $\overline{x}$, you use the following expresion

$\overline{x} = \frac{x_1 + x_2 + \cdots + x_n}{n}$

where $x_1,x_2.\dots,x_n$ are the quantities.

In our case the mean is 130, i.e. $\overline{x}=130$ and the quantities are 104, 137, 154, 131 and x. So, according to the last equation, we have

$130=\frac{104+137+154+131+x}{5}$

solving for x we have the next steps:

$130 \times 5 = 526 + x$

next we multiply in the left side and then substract 526 to obtain

$x= 124$

that is the answer.