Friday, September 28, 2007

MCDL 2.5

Questions and Comments:

Multiplication of Real Numbers

11 comments:

Anonymous said...

d.c.

is this chapter i have trouble simplifing the variable expression. for example if it gives you 5(-a)(-a)(-a) i am not sure what the steps for this is.

Anonymous said...

J.B

The other problem i have stuggled with is adding sutracting, multiplying and dividing negitive integers. Like in problem #27 on page 96 it is not making sense how to multiply thoes. Here is the problem:
(-4)(-7)(3/7)

Anonymous said...

CVDV

real numbers

what are real numbers? in the book all the information it gives about these "real numbers" is that all the numbers in this book are real numbers. i know mrs. leckman said that real numbers are numbers plotable on a real number line however, pi is a real number and it is not plotable on a number line so is 1/3. the only true mathmatical deffinition i have is a definition out of one of my dad's graduate school textbooks and it dosnt make sense.

Anonymous said...

RW

Im having trouble with multiplication of fractions. i just dont really remember most of it because i forgot.

Anonymous said...

I was confused here with multiplication of real numbers. I was able to multipy the real numbers, but on some of the problems, the numbers were all run together. At the time, I did not know that they were supposed to be simplified with the distrubutive
property. Then, after I simplfied, I solved the problem both ways, and came up with two different answers. I dont know if I multiplied or added wrong, or if I just simplified wrong...
An example is (3*5)(-7)(-65*2)What would I do here?-A.L.

Anonymous said...

D.M.
I need help claifying something. When you have exponents in a multiplcation problem, such as -3 to the fourth power, the answer will be positive right? I want to make sure that if you're finding the answer to a problem and when the exponent is even, though the number is a negative, it will always turn out to be a positive number.

Anonymous said...

A.H.
to D.C.

If you are given 5(-a)(-a)(-a), the first step is to combine like terms. -a x -a is positive a squared, because a x a is a squared and two negatives cancel. Then the equation becomes 5(a^2)(-a). Then you take a^2 and x by -a, to get -a^3. Your equation becomes 5(-a^3). Depending on x, you can further solve the equation.

Anonymous said...

E. Mu. to CVDV

real numbers like you and ms leckman said are numbers that can be plotted on a number line, which means they cannot be like pi. numbers that are real numbers terminate. pi is a nonterminating number which makes it impossible to plot on a line plot. also, a number that has a decimal that repeats for ever is not a real number because you cannot exactly plot those types of numbers.

Anonymous said...

iw to dm
if u hav a negative number then hav it at an exponent were the exsponent is even the answer will be postive...odd exponent and negative number = a negative answer
iw to dm

Anonymous said...

E.H To J.B.

There is an easy rule to remember, when multiplying to negatives syou will always get a positive, its the same rule for dividing two negative numbers, also, when adding two negative numbers you will always get aa negative, now when subtracting a negative by a negative it depends, if the negative you are subtracting from is smaler then the number you are taking away, its a positive

Anonymous said...

DG
Hey guys! I don't have a problem with multiplying real numbers, but I have trouble with writing expressions for real life problems in this chapter.
An example that I was struggling with was on our homework last week on 2.5 #34.
This was the question:
There is a slow leak in your bike tire. It is losing at a rate of 2.6 pounds per square inch per day. Let x represent the amount of air in the tire right now. Write an expression for the amount of air in the tire after 3 days. If the amount of air in the tire is now 74.5 pounds per square inch, find the amount of air in the tire after 3 days.
Can someone please show me step by step how to write an expression for this particular situation?
Thnx guys! :D