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joemalatt
Jan 5, 2005, 03:06 PM
I NEED TO RAISE MY MATH SCORE JUST A LITTLE TO BE ABLE TO GET INTO RADIOLOGY SCHOOL. CAN YOU HELP ME OUT??
Can you direct me to the steps on how to do these problems?

1. 100/36 = 45/x
2. x = 4 (72) to the 2nd power/40
3. x/50 = 46/92
4. 90x - 9 + 23x + 35 = 0
5. 68/45 = 70/x
6 4x + 3 = 21 + 3x
7. 7 + 13x - 8 = 35 + 2x
8. x = 100 (52) to the 2nd power / (40) to the 2nd power
9. x = 9 (36) to the 2nd power /(72) to the 2nd power
10. 21x + 45 - 7x = 90

urmod4u
Jan 5, 2005, 09:30 PM
Labman will be glad to help you. Normally, over here, children of age 12-13 years old solve these without problems.

CroCivic91
Jan 6, 2005, 09:15 AM
I will explain you how to do a few of these, and you should be able to do the rest.

First of all, these groups of problems are solved in the same way.

-------------------
1. 100/36 = 45/x
2. x = 4 (72) to the 2nd power/40
3. x/50 = 46/92
5. 68/45 = 70/x
8. x = 100 (52) to the 2nd power / (40) to the 2nd power
9. x = 9 (36) to the 2nd power /(72) to the 2nd power
-------------------

For example:
8. x = 100 (52) to the 2nd power / (40) to the 2nd power
That is equal to:
x = 100 * (52*52) / (40*40)
You because 100=10*10 and 40=4*10, you can write that as
x = 10 * 10 * 52 * 52 / (4 * 10 * 4 * 10 )
You can divide 10 by 10 now and get 1 so that is equal to
x = 52 * 52 / ( 4 * 4 )
Now because 52 = 18 * 4 you can write that as
x = 4 * 4 * 18 * 18 / ( 4 * 4 )
Now when you divide 4 by 4 you get 1 and you are left with
x = 18*18
Now you should know how to multiply that ;)

For another example:
1. 100/36 = 45/x
Now if you multiply that by "x" you get
x*100/36 = 45
Now if you multiply by 36 you get
x*100=45*36
Now divide by 100 and you get
x = 45 * 36 / 100
Because 45=9*5 and 36=9*4=9*2*2 and 100 = 5*2*5*2 you can write that as
x = 9*5*9*2*2/(5*2*5*2)
Now you can divide 5 by 5 and 2 by 2 to get 1 and you end up with
x = 9*9/5
Which is
x=81/5

-------------------
4. 90x - 9 + 23x + 35 = 0
6 4x + 3 = 21 + 3x
7. 7 + 13x - 8 = 35 + 2x
10. 21x + 45 - 7x = 90
-------------------

These are pretty much the same, so I'll show you only one here.

7. 7 + 13x - 8 = 35 + 2x
If you subtract 2x from both sides, you get
7 + 13x - 8 - 2x = 35 + 2x - 2x
Now because 7 - 8 = -1 you get
11x - 1 = 35
Now if you add 1 to both sides you get
11x - 1 + 1 = 35 + 1
Which is
11x = 36
Now divide by 11 and you get
x = 36/11



Work out the rest, it's not very hard!

;)

eawoodall
Jul 2, 2005, 12:22 AM
if you can afford it, there are guides to mathematics available in stores.
They should help you, greatly. If you cannot afford new math college guides then used textbooks from halfpricebooks.com or another book seller like ebay.com

a math review search on abebooks (which is name of search for books at half price books) showed a "cliffs quick review basic math and pre algebra" for one dollar (about 2 dozen at that price), with 2.99 shipping and handling, which is cheaper than 10 dollars for a new cliffs review basic math and pre algebra I priced in a store last week. All bookstores should have a selection of basic review books for college about math.

be sure and buy a basic math book, not the subject specific GRE math book (that is for math majors to pass to take graduate math classes at college). The basic GRE book is okay because it reviews math and english, but maybe you want lower grade level information.

hope these sources of books that can more fully explain the rules of math help you. Also consider whatever college has the courses you are interested in taking should have the textbooks they use for the classes you want to take. Some common titles are "pharmacy calculations" or "drug calculations", and since they are the textbooks for health care they should explain better what type of math practice that would hold the most value to you.

secondly:

ratio problem.
if x is in denominator, multiply by both denominators, divide to isolate x.
if x is in numerator, multiply by denominator under x, if needed isolate x.

100 is to 36 as 45 is to x.
100:36::45:x.
100/36=45/x.
36x (100/36) = 36x (45/x).
100x = 36(45).
100x/100 = 36(45/100).
x =1620/100 = 16.2

72^2 * 4 /40 = 72*72 * 1/10 = 518.4

x/50 = 46/92 (multiply both sides by fifty)
x = 2300/92 = 25.

90x - 9 + 23x + 35 = 0 (combine like terms, and subtract constants to move)
(90 + 23) (x) + (35-9)(1) =0.
113x + 26 = 0.
113x +26 -26 = 0 -26.
113x = -26.
113x/113 = -26/113 = x <> -0.230088496

68/45 = 70/x (multiply by 45x).
68(45x)/45 = 45x(70)/x.
68x = 45(70). (divide by 68 to isolate x).
68x/68 = 45(70)/68 = x =3150/68 <> 46.32352941

4x + 3 = 21 + 3x (combine like terms, isolate x).
4x -3x +3 -3 = 21 -3 +3x -3x.
x = 18.

7 + 13x - 8 = 35 + 2x (combine like terms, isolate x.)
13x -2x + 7-7 + 8-8 = 2x -2x + 35 -7 +8.
11x = 0x +36.
11x/11 = 36/11 = x <> 3.27272727

100 * (52^2) / (40^2)
(52^2) * 100 / 1600
(52^2)/16 = 169.

9 * (36^2) /(72^2) = 9/4 = 2.25

21x + 45 - 7x = 90 (combine like terms)
(21 -7)x +45 -45 = 90 -45.
14x = 45.
14x/14 =45/14 = x <> 3.2142857

again let me say that any of the books I mentioned or any text book on basic math and pre algebra or even algebra should help you. Do not buy a book on calculus, you are not ready for that yet. Hope that helps.

fredg
Jul 4, 2005, 06:11 AM
Hi,

100/36 = 45/x

I will explain just one of these; the others similar are done the same way.
It's call "cross multiplication", and if you write out the problem on a piece of paper, you would have:

100 over 36 = 45 over x

Then multiply 100 times x; and then multiply 36 times 45; gives you:

100x = 1,620

Divide 1620 by 100; and you get x = 16.2

fredg

dayron
Mar 28, 2007, 02:11 PM
I NEED TO RAISE MY MATH SCORE JUST A LITTLE TO BE ABLE TO GET INTO RADIOLOGY SCHOOL. CAN YOU HELP ME OUT???????
Can you direct me to the steps on how to do these problems?

1. 100/36 = 45/x
2. x = 4 (72) to the 2nd power/40
3. x/50 = 46/92
4. 90x - 9 + 23x + 35 = 0
5. 68/45 = 70/x
6 4x + 3 = 21 + 3x
7. 7 + 13x - 8 = 35 + 2x
8. x = 100 (52) to the 2nd power / (40) to the 2nd power
9. x = 9 (36) to the 2nd power /(72) to the 2nd power
10. 21x + 45 - 7x = 90
I need help with a tes that I have tomorrow