Question 511071: Hi, I homeschool my son so please don't assume I'm a student asking for help. I graduated in 1975 so math has changed a bit since my day. I didn't like math in school because I couldn't understand it without an answer to my 'why?' questions. My school system was huge and overcrowded so teachers didn't have time for one-on-one. (Just giving you my background since I may be asking more than one question) I am trying to concentrate on helping my son finish by the end of October while at the same time my oldest step-daughter is on my mind. She is only 34 and had a massive stroke a few months ago..she is married, but with 3 little daughters and them living 900 miles away..it's been difficult to say the least.
So...my question right now is for a particular problem. I don't understand why, in Algebra, you can't simplify the following problem as I have shown. For some reason I can't wrap my head around this and it's causing my teaching skills to 'hiccup'. 9x + 3y - (5x + y) This is how I would do it: 9x + 3y - 5x + 1y =
(12xy) - (6xy) (which equals 6. Why go through all that minus stuff and moving around the numbers... the answer is the same, right? Thank you.
Answer by mananth(16946)   (Show Source):
You can put this solution on YOUR website! You may have your own logic. I appreciate it.
In Algebra , rules govern the method of solving any problem.
when we say xy it means x multiplied by y . So instead of adding you are mulyiplying.
you have 10 apples and 6 oranges.
Can you adod both of them and say you have 16 oranges OR 16 apples.
The answer is NO.
if you have 10 mangoes and another 6 mangoes you can say I have 16 mangoes.
Same is the case with x & y
You cannot add x & y
If you have to add x & y then the answer is x+y and not xy.Both are like add mangoes.
But if you have 6x & 4x Then you can add them and say 10x. They are called like terms
If you need a write up write to me I will send one. Probably your concepts will clear.
Algebra has not changed for years
m.ananth@hotmail.ca
9x+3y -5x+y
9x-5x+3y+y
4x+4y
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