00:01
Okay, so for this question, we want to show that the function, f of x is equal to a, x plus b is invertible, and we want to find its inverse.
00:10
So to prove that it's invertible, we have to prove that it's one to one, and also has to prove that it's onto, which i'll prove later.
00:19
So to prove one to one, we have to show that if f of x is equal to f of y, then this implies that x is equal to y.
00:28
So if we just substitute what we have into these equations, we have a, x plus b, because that's f of x, and f of y is a, a plus b.
00:39
So subtracting the bs together, you have ax is equal to a, divide the a, you have x is equal to y.
00:47
So therefore, it's one to one.
00:49
And therefore, f of x is one to one.
00:55
Now, to prove it's onto, it's probably easier first to find the inverse of this function...