Given the set: {1,13,-7,8,x,-2,-9,2} , for what x would the mean of the set be 0?

1 Answer
Dec 28, 2015

x=-6

Explanation:

color(white)(xx)bar a =1/nsum_(i=1)^n a_i (the mean of a set of n data points)

color(white)(xx)0=1/8sum_(i=1)^8 a_i
=>(x-9-7-2+1+2+8+13)/8=0

Multiply both sides by color(red)8
color(white)(xx)color(red)(8xx)(x-9-7-2+1+2+8+13)/8=color(red)(8xx)(0)
=>x+6=0

Add color(red)(-6) to both sides
color(white)(xx)x+6color(red)(-6)=0color(red)(-6)
=>x=-6