Question 30387: I have simplified the problem from (x^3+3x^2-7x)-(-4x^2+5x-8) to x^3+(3x^2+4x^2)+(-7x-5x)+8 .(sorry, I don't know how to type exponents) is this correct so far? and also, what would I do with the x cubed? can I combine it with the 3x squared and the 4x squared to make 7x to the 5th power? PLEASE help!
thanks,
Bethany M.
Answer by longjonsilver(2297)   (Show Source):
You can put this solution on YOUR website! as is usually the case, those students who do not understand something in maths, invariably do much harder things than is actually needed.
First, to mutliply the second bracket by the -1 written before it... the full writing of the question should be:
 but mathematicians are lazy and we miss out some bits. The thing is we all know they have been missed out. Trouble is, when you start maths, you do not know it has been missed out, especially if your teacher doesn't teach it that way.
Basically, all that has happened, is that all the signs have been flipped.
Now, we can collect like terms... we have  and  and  and terms with just numbers.
So, how many terms are there? Answer is 1 -->
how many terms are there? Answer is 3+4 --> 
how many terms are there? Answer is -7-5 --> 
how many pure numbers? Answer is 8
So, the answer is  .
And i hope you can see that this is a lot easier than what you were trying to do.
jon.
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