I am now working on Solving Systems of Linear Equations. I was shown 3x - 2y = 7 and 6x - 2y = 4. First I multiply one set by -1 {I'll use the second set for this part.} The second set becomes -6x + 2y = -4. Then I add that to the first set, which gives me -3x = 3. Solving the equation, this tells me that x=-1 and y=-5. [Did I get this right?] My questions are: #1.} Why is one set multiplied by -1 before adding the two sets together? #2.} Where in today's world would I be using this?

[BTW ~ I am not in any school. It has been more than 30 years since I was in school. I have ALWAYS loved math, and usually am running numbers through my mind and playing with them. One time, I was in bed, JUST about ready to fall asleep, and 2 compound fractions came in my mind. My brain told me, "O.k., divide these two fractions." I was thinking, "Oh, COME on! I am just about ready to nod off! But, IN BED, and JUST about ready to fall asleep, I was able to divide those two fractions in my head!.]