Please resolve (3x+5)(2-x)-(2-x2)

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Request for Question Clarification by mathtalk-ga on 22 Dec 2004 11:57 PST

Hi, peoman-ga:

Do you mean "simplify" the expression?

regards, mathtalk-ga

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Clarification of Question by peoman-ga on 22 Dec 2004 12:32 PST

Well, we should be able to give a value to x.

Also, please note that in the last expression (2-x2), x2, means x square

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Request for Question Clarification by mathtalk-ga on 22 Dec 2004 13:03 PST

Okay, but to give a value for x, we need an equation to "solve".

So far you've only given a polynomial expression involving x:

(3x+5)(2-x)-(2-x^2)

Perhaps you meant this:

(3x+5)(2-x) = (2-x^2)

regards, mathtalk-ga

First, remember the order of operations:
In this case you have multiplication, addition and subtraction... so
multiplication comes first.  So to start, multiply those first 2 sets
of parenthesis (remember to distribute).
After you do that, simply find the like terms (5x and 2x are like
terms for example since they both have the same power of x) and add or
subtract them as the equation requires (based on the sign,+ or -,
before the term).
Once you have combined all like terms then you have simplified the
equation all that you can.

(3x+5)(2-x)-(2-x2) =
(3x+5)*2 - (3x+5)*x - (2-x2) =
(6x + 10) - (3x2+5x)  - (2-x2) =
6x + 10 - 3x2 - 5x - 2 + x2 =
-2x2 + x + 8 -> this is the solution

If your equation is equal with 0 then you'll have
  x_1 = ( -1 + sqrt(65) ) / -4
  x_2 = ( -1 - sqrt(65) ) / -4

mathtalk-ga's idea does make a lot more sense in the way math problems
are constructed for homework. They don't tend to have "weird" answers
at the level suggested by the question.

Although, after I say that, wouldn't the RHS be "easier" if =(4-x^2)? 

peoman-ga: Are you dealing with quadratic formula in this math section
or are you just trying to reduce/simplify the expression? That is,
mathtalk-ga is correct -- you cannot solve for x if you don't have an
equation with an = sign. You can reduce the expression as jupan-ga
commented above, though.

Phew, this is tough work for an algebra question.  I'm breaking a sweat.

Okay, jack, I'll get this side of the equation and you pick up the other.

1,2,3... oops, sorry.  My hands slipped.  Hey, we broke it!

Umm, let's just leave the pieces there.  Maybe no one will notice.

--mt