Given the set: ${-6,x,7,11,29,-4,-5}$ , for what x would the mean of the set be -9?

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Answer 1 · 2015-12-11T08:57:12

$color(white)(xx)x=-95$

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

$color(white)(xx)-9=1/7sum_(i=1)^7 a_i$
$=>(-6+x+7+11+29-4-5)/7=-9$

Multiply both sides by $7$
$color(white)(xx)color(red)(7*)(-6+x+7+11+29-4-5)/7=color(red)(7*)(-9)$
$=>x+32=-63$

Add $-32$ to both sides
$color(white)(xx)x+32color(red)(-32)=-63color(red)(-32)$
$=>x=-95$

Given the set: {-6,x,7,11,29,-4,-5} {-6,x,7,11,29,-4,-5} , for what x would the mean of the set be -9?