Math problem help

[2001300exguy]

this is for my precalc class as a problem of the week and i am completely clueless, could some of the math buffs on here help me out, here it is:

Find three consecutive odd integers such that 4 times the first is 8 less than than 3 times the sum of the last two.

I have to show all of my work and provide the answer in sentence form, thanks to anyone that helps.

wow im so glad im outta school...thanx for the reminder...sorry i cant help, im dumb

[2001300exguy]

lol the rest of the class isnt to hard but she said these are meant to expand our thinking abilities or something

[400exstud]

First, find the answer via trail and error. Then see if you can't work backwards.

[GPracer2500]

first number = -5
second number = -3
third number = -1

(-5)*4 = -20

-3 + -1 = -4
(-4)*3 = -12
-12 - 8 = -20

It can't be any possitive numbers. Take any two consecutive possitive odd numbers, sum them, take that times 3, subtract 8, and divide by 4 and your answer will always be larger than any of the numbers you started with. So, no possitive numbers will work.

[ZSK]

It's not hard at all,

You have three terms in which to deal with:

X
X+/-2
X+/-4

This is the order in which they acend or decend. Ex. 7 9 11 or 11 9 7

Setup your equation.

4 times the first---4X
is--- =
8 less than ---- 4X-8
3 times the sum of the last two --- 3(X+/-2+X+/-4)

Set it up first for the terms X X+2 and X+4

4X-8= 3(X+2+X+4)
4X-8= 6X+18
4x= 6X+26
0= 2X+26
-26=2X

X=-13

Plug -13 back in to see if the answer works out.

4(-13)-8=3(-13+2-13+4)
-52-8=3(-20)
-60=-60

-13 -11 and -9 work out to be your answer

But consecutive works both ways,

4X-8= 3(X-2+X-4)
4X= 3(2X-6)+8
4X= 6X-18+8
4X= 6X-10
-2X=-10
X=5

Plug 5 in and check it

4(5)-8=3(5-2+5-4)
20-8= 3(4)
12=12

5 3 1 also work either and both answer is correct.

[fatkid400]

Wow:huh I agree with honda86.I dont miss school!! I'm glad I only have to deal with trig instead of calc.... I cant remember any of that stuff.

[XCAdam89]

Originally posted by ZSK
It's not hard at all,

You have three terms in which to deal with:

X
X+/-2
X+/-4

This is the order in which they acend or decend. Ex. 7 9 11 or 11 9 7

Setup your equation.

4 times the first---4X
is--- =
8 less than ---- 4X-8
3 times the sum of the last two --- 3(X+/-2+X+/-4)

Set it up first for the terms X X+2 and X+4

4X-8= 3(X+2+X+4)
4X-8= 6X+18
4x= 6X+26
0= 2X+26
-26=2X

X=-13

Plug -13 back in to see if the answer works out.

4(-13)-8=3(-13+2-13+4)
-52-8=3(-20)
-60=-60

-13 -11 and -9 work out to be your answer

But consecutive works both ways,

4X-8= 3(X-2+X-4)
4X= 3(2X-6)+8
4X= 6X-18+8
4X= 6X-10
-2X=-10
X=5

Plug 5 in and check it

4(5)-8=3(5-2+5-4)
20-8= 3(4)
12=12

5 3 1 also work either and both answer is correct.

Exactly. I learned this in Algebra 1. The First is X, then the following ones go X, X+2, X+4, ect because you are trying to reace the next Postive or Negative Integer, you have to account for the gab in between. For instance, if you start on 1, you have two numbers to go until the next odd integer, make sense?

Then, after you get your formulas strait, (X, X+2, ect) you simply plug them in, and solve.

[2001300exguy]

yea i got it thanks fot the help

[ilpadrino113]

ya i wishi could say i don't miss school, i still got a 2 years left of college, but all my math classes are done so ya i don't miss math. Good luck with that by the way.

[400exrider99]

im still in school but i didnt have to take math last year and i dont nead to know any more of it. thank god

[Mx_523]

Holy ****. I go back to school Monday. This is what I have to look forward to.:chinese: :chinese: :chinese: