00:01
Okay, for this question, we're going to find the values of the variable for which the expression is defined as a real number.
00:07
Really quick here on my end for the website, these plus or minuses here come up all wonky.
00:17
So i would just make sure that this really is negative 6x minus 72.
00:23
And if not, we're using the same process, so you can kind of base your answer off of this one.
00:28
So what i'm going to do is set it equal to 0, and we want a factor.
00:34
So we're saying what multiplies to negative 72 and adds to negative 6.
00:40
So if we think about the factors of 72, the big one that jumps out at me is 12 and 6, right? and so we know one is going to have to be negative, and one is going to have to be positive in order to get this negative 72.
00:55
And we know that our 6 is going to be negative up here, which means our bigger number has to be negative, because negative 12 plus 6 is going to give us negative 6.
01:10
So we factored, we set it equal to 0, and now we're going to set each term equal to 0.
01:17
So x minus 12 equals 0, and x plus 6 equals 0...