00:01
So two numbers that give a sum of 8 and product of 10.
00:03
So x plus y is 8 and xy is 10.
00:11
So we have x is 10 over y.
00:14
So let's plug that into the first equation here.
00:17
So 10 over y plus y is 8.
00:22
Well, we have a y on the bottom.
00:24
So let's multiply everything by y to cancel that out.
00:27
So 10 plus y squared is 8y.
00:32
Let's put everything on one side now.
00:33
So y squared minus 8y plus 10 is equal to 0.
00:41
So in this case, we want to find two numbers that give a sum of 10 and a product of negative 8.
00:50
In this case, we cannot do any factoring.
00:54
So we need to use our quadratic formula.
00:58
So our quadratic formula is the following...