00:01
For this problem, we're told that x is equal to 1 6th minus 5 3rds of negative 2 5ths divided by 4 over 9.
00:17
And then we want to ultimately use that to find the value of x cubed minus 3.
00:23
So the first thing i'm going to do is i'm going to deal with all of this.
00:26
So when i have compound numerators and denominators, i can rewrite it as the numerator times the reciprocal of the denominator.
00:35
So then i can cancel some things out.
00:38
And so that makes this negative 9 over 10 when i multiply across the top and across the bottom.
00:45
So i can rewrite my x is equal to 1 over 6 minus 5 over 3 over negative 9 over 10.
00:54
So now i'm ready to deal with this numerator.
00:56
So i can't just subtract these because i don't have like denominators.
01:00
So to make 3 and 6 the same, well, if i multiply 3 times 2, that makes 6.
01:06
But i can't just multiply a denominator by something.
01:09
I have to do the same thing to the numerator so i don't change any values.
01:12
So i can rewrite this as x is equal to 1 over 6 minus, multiply across the top, and then multiply across the bottom.
01:21
Them.
01:21
Now i've got my like denominators there, and then this is all over negative 9 over 10.
01:27
All right, so 1 over 6 minus 10 over 6 is negative 9 over 6 over negative 9 over 10...