00:01
So we have x over 9 minus 8 over x is equal to 1 .9th.
00:05
So our denominators are 9, x, and 9.
00:08
So our lcd is just a product, 9 times x or 9x.
00:13
So to get a denominator of 9x from x over 9, we just multiply by x over x.
00:20
So we get, well, x times x is x squared.
00:24
So we get x squared over 9x, and then we multiply 8 over x by 9 over 9.
00:34
So 8 times 9 is what? 72.
00:39
This is minus 72 over 9x is equal to, well, 1 9th, we multiply by x over x over x.
00:48
So it's equal to x over 9x, right? to get like denominators everywhere, because what we can do now is combine the left -hand side.
00:59
So we get that x squared minus 72 all over 9x is equal to x over 9x.
01:12
But now since our denominators are exactly the same, the numerators must be the same.
01:19
So all we have to do now is we can get rid of our fractions and set our numerators equal to each other.
01:26
So we have x squared minus 72 is equal to x.
01:33
So we can subtract the x to the other side and get a quadratic in standard form...