a few more confusing problems...

[dimava]

I have a few problems which are really confusing me, if someone can do one of these out for me, i'd appriciate it.

y^2-9         8
-------    X  -----
   4             y+3


s^2 + 2s - 8            s+5
----------------   X   -----------
s^2 +3s -10           s^2-16



5m                25m^2
-------     /    ------------
m+1             m^2 + 2m +1

thanks,

Dimava

[opus]

The first one
-1- (y^2-9)/4 * 8/(y+3)
-2- ((y^2-9)*8)/(4*(y+3))
-3- ((y+3)*(y-3)*8)/(4*(y+3)) remember the 3. Binom?
-4- ((y+3)*(y-3)*2)/(1*(y+3))
-5- ((y+3)*(y-3)*2)/(y+3)
-6- (y-3)*2)
-7- 2y-6

[opus]

The third comes to
1/5* (1+1/m^2)

[DiGiTaIErRoR]

The second comes to:

 1
---
s-4

[DiGiTaIErRoR]

Originally posted by opus
The third comes to
1/5* (1+1/m^2)

I got

m + 1
-----
 5m

For the third.

Your solution has the m's squared. Otherwise we got the same solution.

[dimava]

a few more problems...

please bear with me i know im posting more than a couple, but i've done a few hundred problems on my own already...

            6
x   -    ------
           x+2
_______________
            8
x   +   -------
            x+5

What are the excluded values of y in the expression 

y^2  +  y  - 2          y^2-5y+5
------------------  *  -------------------
y^2 - 2y - 15           y^2 + 5y +6

Use long division to find the quotient 

(t^2 +4t -6) / (t+5)

An airplane can fly at a rate of 525 mi/h in still air. It can fly 2800 miles with the wind in the same time that it can fly 2450 miles against the wind. Find the rate of the wind.

I attached this problem because it uses subscripts

If somebody can help me out with a few of these i'd really appricate it. And if possible I would like to see how you got the answer so I can learn from it.

thanks,

Dimava

[opus]

Originally posted by DiGiTaIErRoR
I got

m + 1
-----
 5m

For the third.

Your solution has the m's squared. Otherwise we got the same solution.

OK, I see my error, thanks

[opus]

For sure I have to do the airplane question:
speed =525 mph
Distance against wind 2450 m
distance with wind 2800 m

2800m/(525mph+x mph)=2450m/(525mph-x mph)

solve that and you get a wind of 35 mph

[opus]

on the second
excluded are all values that will leed to a division thru 0.

first one
y^2 -2y-15
same as (y-5)*(y+5)
which would be 0 if y=5 or y=3

second one
y^2+5y+6 will only by = if y=-2

So excluded are -2 , 3 and 5

[dimava]

thanks, wouldn't it be 5, -2, -3 though?

[opus]

You're correct, sorry
it must read:
first one
y^2 -2y-15
same as (y-5)*(y+3 )
which would be 0 if y=5 or y=-3

[opus]

on the last one

1/Rt=1/R1 + (1/(R2 +R3)) | -(1/R1)
1/Rt -1/R1=1/(R2 + R3) | * (R2 + R3)
(1/Rt -1/R1)*(R2 + R3)=1 |/(1/Rt -1/R1)
(R2 + R3)=1/(1/Rt -1/R1) | -R3
R2= 1/(1/Rt -1/R1) -R3

R2= 1/(1/2 - 1/5) - 3

R2=1/3

[dimava]

ok sounds good thanks

now if i could get the 1st and 3rd, it would be perfect

[opus]

The first puh, er, ?????
The third, what is a Long division?

[opus]

on the third I only get

(t^2+4t-6)/(t+5)
(t+5)*(t-1)-5/(t+5)
[(t+5)*(t-1)/(t+5)] -5/(t+5)
(t-1) - 5/(t+5)