Help with 8th grade math question

[SW FL Dem]

It's late and it has been a long day. My son needs to answer this question and my brain isn't working.

In the table below, n,p,r and t each represent a different integer. If n = -4 and t is not equal to 1, find each of the following values. Explain your reasoning using the properties of integers

n x p = n
t x r = r
n + t = r

find the values for p, r and t.

[WindRavenX]

1. wtf

I can't do that shit- and that's for 8th graders???

[SW FL Dem]

3. Unfortunately, it's an FCAT practice question

thanks to Jebbie and the NCLB

[physioex]

23. Come now....

It's not that hard. You can tell what p is by reading the first line.

[Dookus]

2. well

p = 1, because any number multiplied by 1 is itself (n x p = n)

For the next two, we have to assume that either T or R = 1 for the same reason as above. The question states T is not equal to 1, so R = 1.

Now we already know N = -4, so the third equation says

-4 + T = 1. So T = 5.

p = 1
r = 1
t = 5

[Guy Fawkes]

5. but that doesn't work...

because "t•r=r" but 5•1=5

[Dookus]

7. hrmm....

my worldview is shaken.

[Dookus]

the OTHER problem

is the question states that they're all different integers.

I think the question is pretty flawed.

[SW FL Dem]

8. Thanks

I got as far as the first step, then my brain shut down.

[Not_Giving_Up]

4. OK, I'm gonna give this a try

n*p=n....p=1
t*r=r....r=1
n+t=r...-4+t=1....t=5

[jdots]

6. sorry i dropped out in the 5th grade to join the freepers.

[RevolutionaryActs]

9. The question must be asked...

Is our children learning? :shrug:

[Guy Fawkes]

10. here ya go:

n•p=n if n=-4, -4•1=-4
t•r=r t=4 r=0 4•0=0
n+t=r -4+4=0

[Dookus]

11. closer...

but the premise states that n, t and r are all different integers.

[Guy Fawkes]

14. they are!

t=4
n= -4
r=0

those are all different

[Dookus]

15. Sorry

I misread your post - I thought you had two zeros.

[Guy Fawkes]

17. s'ok...

I do it all the time (often with hilarious results)

[JI7]

12. value of p,r, and t is 1

n=0


on edit, forget it, i didn't read what you wrote, just saw the problem

[Floogeldy]

19. No. n= -4

[gbwarming]

13. p = 1. any non-zero number times one is that number.

The second equation looks like the first one, but they told us t is not one, so r has to be something that can be the same number. try zero.

so n= -4
p=1
r=0
last part is easy

[The_Casual_Observer]

16. r =0 if t is not equal to 1. then t = 4

hope you get this before tomorrow AM.

[Sushi-Lover]

18. Ok .. kinda hard to do in text but

On edit, what we just learned is that DUers can do algebra and I type slowly :)

[SW FL Dem]

20. THANKS!

I got the answer and the kid and I can go to bed. DUers are awesome!!

[HamstersFromHell]

21. Here goes...

If n x p = n then p has to be 1

-4 x 1 = -4

Now in order for t x r = r to be true, it'd only work if r = 0

t x 0 = 0

Now n + t = r solves to -4 + t = 0, then t has to be 4

n = -4
p = 1
t = 4
r = 0

Hammies!

[Kali]

22. Don't stress

this is a chance for your child to become aware that adults and authority in general can be MISTAKEN.

I can't tell you haw many Stupid math problems I have tried to work for hours, finally giving up with anote to teacher - only to have a reply like OH sorry that was a misprint or we couldn't do that one either.