write and solve an equation to find value of variable
104,137,154,131, x; mean = 130

Question

write and solve an equation to find value of variable 
104,137,154,131, x; mean = 130

amistre64 · Answer

how would you go about finding the mean of a set of data like this to begin with?  spose that x is already some known value

anonymous · Answer

add i believe

amistre64 · Answer

adding is a good step, after you add them alltogether, then you would want to divide by something right?  what would we want to divide it by?

anonymous · Answer

4 or 5

amistre64 · Answer

hmm, lets stick to 5 since we want to count x as a known value :)  so, this gives us

$$\frac{104+137+154+131+x}{5} = 130$$

now, how would we go about getting x all by itself?

anonymous · Answer

so whatever i get i just put x as 1

anonymous · Answer

OMG OMG OMG, Im on teem Jake also! *virtual high five*

anonymous · Answer

haha

amistre64 · Answer

no, x is unknown so it makes no sense to just put  x as 1; but since we have an idea what to do with x if we DID know it; then this is the setup that we would take

amistre64 · Answer

once we know the setup, it should be pretty basic to rearrange the equation to solve for x

anonymous · Answer

ok could you help put it in the order

amistre64 · Answer

sure, how do we undo that 5 in the denominator?

anonymous · Answer

well since we divided didnt we use it already

anonymous · Answer

i dont know if its right but i got 127

amistre64 · Answer

we havent done any math tey, we have just taken the information and put it into a format that we can work with as opposed to some abstract wordings.

$$\frac{104+137+154+131+x}{5} = 130$$
to get to the x, lets multiply everything by 5
$$\cancel{5}*\frac{104+137+154+131+x}{\cancel{5}} = 130*5$$
$$104+137+154+131+x = 130*5$$
now its just a matter of subtracting the knowns from the left and right in order to evaluate x

anonymous · Answer

so we subtract now

amistre64 · Answer

correct

anonymous · Answer

just the basic numbers together?

amistre64 · Answer

yes; if you want to add up all the numbers and then subtract the total amount from each side, thats fine

amistre64 · Answer

what is:  104+137+154+131 ?

anonymous · Answer

526

amistre64 · Answer

then x should be  130*5 - 526

anonymous · Answer

124 k great i get it now thanks alot

amistre64 · Answer

$$104+137+154+131+x = 130*5$$
$$526+x = 130*5$$
$$x = 130*5-526$$

amistre64 · Answer

good luck