Video Transcript
Determine the common domain of the
functions 𝑛 one of 𝑥 equals negative seven divided by 𝑥 minus seven and 𝑛 two of
𝑥 equals negative eight divided by 𝑥 squared minus 64.
To find a common domain, we need to
set the denominators equal to zero, solve for 𝑥, and then exclude those values. So the reason why we set the
denominators equal to zero is because the denominators are on the bottom, and you
never want to divide by zero because that would give you an answer that is
undefined. So we set our denominators equal to
zero, solve for 𝑥, and we will exclude these values.
So let’s add seven to the left
equation and then add 64 to the right equation. So we already know we’re gonna have
to exclude seven. And on the right equation, let’s
square root both sides. So we get 𝑥 equals eight and 𝑥
equals negative eight because the square root of 64 is positive eight and negative
eight.
So the common domain between these
functions would be all real numbers minus negative eight, seven, and eight.
