Question

A social networking site recorded that 80% of the people who became members of the site one month were between 30 and 40 years old. The equation below represents this information, where x represents the total number of people who became members of the site that month.

x = 0.8x + 72

How many people who became members of the site that month were between 30 and 40 years of age

Answer 1

so you want to solve for x. any ideas on your first step?

Answer 2

no

Answer 3

ok so let's try this\[x=.8x+72\]

now can you get the x terms on the same side?

Answer 4

sorry try this \[3x=4x+5\]

Answer 5

dont you do this:
subtract 5 on both sides and then after that divide?

Answer 6

not quite, you want to get only x terms on the left(or right) and only non x terms on the other side. can you tell me which terms are 'x-terms'?

Answer 7

3x and4x

Answer 8

good so if you want to isolate x (aka get all the x terms together on one side) what do you need to do?

Answer 9

subtract 3x from 4x

Answer 10

can you show me this please?

Answer 11

its going to be x which is basically 1x

Answer 12

but can you write the equation/ show me your work; otherwise, I cannot see if you did it correctly

Answer 13

ex. \[6x=4x\]\[6x-4x=0\]\[2x=0\]

Answer 14

3x=4x+5
-3x -3x
1x=5
x=5

Answer 15

right?

Answer 16

well not quite if you subtract 3x from both sides as you did you will get\[0=x+5\]

Answer 17

do you see why?

Answer 18

no

Answer 19

First of all for solving this question do you know the conception of : Theory of equations.

Answer 20

no

Answer 21

ok good night this is to much for my brain

Answer 22

uh ok