00:01
Okay, so i know that the total number of facebook, instagram, and twitter users are 223 million.
00:07
So i'm just going to write 223 and abbreviate million at the end.
00:11
I also know that the number of instagram and twitter followers, so if i were to add those two together, is 23 less than the number of facebook users.
00:22
So 23 less is a turnaround word, so it'll be f minus 23.
00:27
If i were to get all the variables on one side, i can rewrite this as negative f plus i plus t equals still negative 23.
00:38
I also know that the number of instagram users is 18 million more.
00:43
So let's follow that in order.
00:44
Instagram is equals 18 more than the number of twitter users.
00:50
If i got i on one side, i'd have i minus t equals 18.
00:55
And now i have a system of three equations.
01:00
Let's solve them.
01:02
So i first want to eliminate f, so i'm going to add one and two together.
01:07
When i do that, the f's cancel.
01:09
I'll get 2i plus 2t equals 200.
01:14
And i could divide by 2 to each term, which will give me i plus t equals 100.
01:21
And this is very similar to my third equation, so i'm going to add this to my third equation...