00:01
We basically want to find the slope.
00:02
So we're going to have f of x equals the square root of x and we want the rate of change from 1 to b.
00:09
So let's find f of 1, which is going to be the square root of 1, or 1.
00:13
F of b is going to be the square root of b, which is the square root of b.
00:18
So we have the order of pairs 1, 1, and we have b, square root of b.
00:24
So if we work this out, that's going to be the square root of b, minus 1, over b, minus 1, and we want that to equal 1, 7.
00:33
So if we multiply out, we're going to have 7, square root of b, minus 1, equals b, minus 1...