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avatar+2448 

1. \(6/a=18/24\)

2. \(2/5=m/15\)

3. \(n-6/3n=n-5/3n+1\)

4. \(3y-8/12=y/5\)

 Mar 5, 2018
 #1
avatar+129899 
+2

We can solve everyone of these by cross-multiplication...so

 

6/a  =  18 /24      cross-multiply

 

24 * 6  =  18 * a

 

144  =  18 *a      divide both sides by   18

 

8  =  a

 

 

I'll  do  the third one....you try the other two, RP....let me know if you get stuck

 

n - 6 / 3n  =  n - 5 / 3n + 1        cross-multiply

 

(n - 6) (3n + 1)  =  3n ( n - 5)      simplify

 

3n^2 - 18n + 1n - 6  =  3n^2 -  15n      subtract 3n^2  from both sides

 

-17n - 6  =  - 15n       add  17n  to both sides

 

-6   =  2n      divide both sides by 2

 

-3  =  n

 

 

 

cool cool cool

 Mar 5, 2018
 #2
avatar+2448 
0

2. 2/5=m/15

Cross multiply: 30=5m

Divide by 5

6=m

4. 3y-8/12=y/5

Cross multiply: (3y-8)(5)=12(y)

ugh idk T_T

RainbowPanda  Mar 5, 2018
 #3
avatar+129899 
+2

6  is correct for the second one  !!!

 

OK....for the last....you have it set up correctly

 

5(3y - 8)  =  12y    simplify

 

15y - 40   =  12y      subtract  15y   from both sides

 

-40  =   -  3y        divie both sides by  - 3

 

40/3   =  y

 

 

cool cool cool

CPhill  Mar 5, 2018
 #4
avatar+2448 
-1

ty <3

RainbowPanda  Mar 5, 2018

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