Equations!Date: 2 May 1995 07:40:45 -0400 From: Milli Kutuphane Subject: (none) x+y=5 xy=3 x^2+y^2=? Date: 2 May 1995 11:13:06 -0400 From: Dr. Sydney Subject: Re: Equations!! Hello! There are a couple of ways to approach this problem... I'll give you a few hints, and then you can see if you can take it from there, okay? First, what if you squared both sides of the first equation? Write out (x +y)^2 = 5^2 and then see if you can see something that will help you solve the problem. A more conventional way of doing the problem would be to first solve for x and then solve for y (or first solve for y and then solve for x). Rewrite the first equation as y = 5 - x. Now Substitute this y in the second equation. Now your second equation has only x's in it, and you should be able to solve for x. Once you have x, figure out what y is, and then plug those numbers into the third equation and see what you get! I tend to think the first way of doing it is neater, just because it involves less work and has sort of a trick involved, but either way will get you the answer you want. If you have any questions about this, write back! --Sydney, "Dr. Math" |
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