Question About System of Equations Problem

TiaharaJBennett said:
-2x + (-3x - 2) = 8
Click to expand...

I do not understand why you're thinking about multiplication.

Please proofread the equation above. In particular, check whether there is something missing between the + and ( above.

Otherwise, can you explain your thoughts? :cool:
 
TiaharaJBennett said:
Because I was told to multiply everything that's inside the brackets by what's outside.
Click to expand...

As you have proofread your typing and found nothing missing, I must tell you that your adviser is wrong.

There IS NOTHING outside the parentheses; that's my point. :eek:

You typed this: -2x + (-3x - 2) = 8


We would only multiply -3x and -2 by some number IF there were some number displayed between the + and (.

Look up "The Distributive Property", in your textbook or elsewhere.


EG1:

-2x + 7(-3x - 2) = 8

In this example, there is a 7 between the + and (.

Hence, we multiply each term inside the parentheses by 7.

Like this: (7)(-3x) - (7)(2)


EG2:

-2x + (1/2)(-3x - 2) = 8

In this example, the number 1/2 appears in front of the parentheses.

We multiply (1/2)(-3x) - (1/2)(2)


EG3:

-2x - 4444(-3x - 2) = 8

In this example, we multiply (-4444)(-3x) - (-4444)(2)


Do you see, now? In what you typed, there is nothing in front of the open parenthesis:

-2x + (-3x - 2) = 8



IF YOU ARE STILL CONFUSED, STOP READING AT THIS POINT.


The only multiplication possible in what you have typed is multiplication by an implied 1.

In other words, were you to realize that there is an implied (invisible) 1 in front of the parentheses, then you could multiply the stuff inside by the 1 outside, but that would be trivial because multiplication by 1 never changes anything!

-2x + 1(-3x - 2) = 8

Distributing the 1 across the difference -3x - 2 would look look this:

(1)(-3x) - (1)(2) = -3x - 2

What a waste of time!

Whoever told you to multiply (-3x - 2) by anything in this exercise is flat-out wrong! (I hope that this person is not your teacher, despite the fact that this would explain a lot of your posts.)
 
mmm4444bot said:
Whoever told you to multiply (-3x - 2) by anything in this exercise is flat-out wrong! (I hope that this person is not your teacher, despite the fact that this would explain a lot of your posts.)
Click to expand...

No, it was not my teacher. I was told here on the boards. Multiplying was what I did for my first system of equations... I guess it's just not the same with this one.
 
TiaharaJBennett said:
No, it was not my teacher. I was told here on the boards. Multiplying was what I did for my first system of equations... I guess it's just not the same with this one.
Click to expand...
You are essentially saying that you were told to multiply for one problem, so you assume you should multiply for every problem! If, while trying to drive to an unfamiliar location, you asked for directions and were told to "turn right at the next intersection", would you then conclude that, to get to any location, you should alway "turn right at the next intersection"?
 
HallsofIvy said:
You are essentially saying that you were told to multiply for one problem, so you assume you should multiply for every problem!
Click to expand...

That's exactly what I thought. When I asked here on the boards if I could use multiplication for every system of equations, I was told yes.
 
Last edited:
TiaharaJBennett said:
When I asked here on the boards if I could use multiplication for every system of equations, I was told yes.
Click to expand...

Good grief. That previous question is not even close to the current context. Your English is vague, sometimes. Math discussion requires clear communication. I have no more time for guessing, but I will offer you some final advice.

You are not ready for Intermediate Algebra. You seemed to have completely skipped beginning algebra. You do not have the prerequisite skills for the exercises that you post about. We cannot teach weeks of introductory material on these boards.

We've given you links to lessons, but you can't understand the lessons. You also seem incapable of expressing specifically what confuses you. I believe the reason why is that you never learned the beginning terminology or concepts and that your communication skills are lacking.

If you do not understand The Distributive Property, you cannot proceed beyond beginning algebra.

I think that you need help from a face-to-face tutor or directly from your teacher. You have a lot of catching up to do.
 
You must log in or register to reply here.
Top