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+--- Thread: Math homework I need help (/showthread.php?tid=28394)
Math homework I need help - Luizao876 - 02-01-2013 07:10 AM
I suck in proportions, so if anybody here can help, I will be grateful.
Here are the questions ( the ?/? are fractions):
B) m/15 = n/6, m - n = 90
C) r/s = 13/5 , r - s = 72
D) 18/x = 8/y, x + y = 104
E) x/8 = y/3 = z/4, x - y + z = 108
F) 15/x = 9/y = 3/z, x - y - z = 42
This is middle school stuff I think, so it shouldn't be so hard to solve them if you are good in Math. I will be grateful for whoever does this for me.
Math homework I need help - Desu - 02-01-2013 07:46 AM
I'm too lazy to do these right now, but, the general way you do these is:
1) rearrange the proportions such that you get the variables in the numerator.
2) on the right side, (m-n = 90 etc.) solve for one variable
3) use that information and put it into the proportion
like for B)
m-n = 90
m = 90 + n
Therefore,
substitute m = 90 + n for m
(90 + n) / 15 = n / 6
dive 90 + n by 15
6 + (n / 15) = n / 6
subtract n / 15 from both sides
6 = (n / 6) - (n / 15)
Solve for n. Once you have n, put n back into the original equation you start with, then solve for m.
RE: Math homework I need help - Luizao876 - 02-01-2013 08:17 AM
Thanks for the help Desu, I was able to finish all of the homework.
RE: Math homework I need help - Heil_Kaiba8921 - 02-02-2013 05:20 AM
freaking smart-ass middle schools...this is what we were learning last semester and i sucked at them because the teacher was dull, demanded respect and never gave you any, and literally put me to sleep even if i was wide awake.
I ended up getting a 57% in his class so i'm in the repeat class for algebra 2 with a better teacher (i know because i had him before and used to go to him all the time for help during study hall)...i do wish that i would have worked just slightly harder to be able to have passed first semester
RE: Math homework I need help - SmokeyTheAggie - 02-02-2013 07:22 AM
I solved F for ya. x = 210, y = 126, z = 42