4 Math problems..... plz help! I'm going crazy?

Question

This may seem simple to you but i'm sooooo lost..plz help!

1.

6 2/13

4

3 11/39

+ ________

2. -5 3/5 / (-100) =

3. 3/7 y = -3/14

4. z/3 + 2 = z/5 +1

Answer 1

1. Are you adding them together?

Add the whole numbers (6+4+3 = 13)

Add the fractions (2/13 + 11/39... Find a common denom... 2/13 = 6/39.... 6/39 + 11/39 = 17/39)

Add the whole numbers & fraction to get 13 17/39.

3. Multiply by 7/3 on both sides.

4. Get the whole numbers on one side and the 'z' terms on the other.  Then solve for 'z'.

Ask your teacher - you seem like you are struggling - for more help!

Answer 2

1)= 13 17/39

2= 7 / 125

3)y = -1/2

4)z = -15/2

Answer 3

1)

(6 2/13) + 4 + (3 11/39)

= (6 + 4 + 3) + (2/13 + 11/39)

= 13 + [(2*3 / 13*3) + 11/39]

= 13 + (6/39 + 11/39)

= 13 + 17/39

= 13 17/39

2)

(-5 3/5) / -100

= (-28/5) / (-100)

= (-28 / 5)(-1 / 100)

= (-28 * -1) / (5 * 100)

= 28 / 500

= 7*4 / 125*4

= 7 / 125

3)

(3/7)y = (-3/14)

(7/3)(3/7)y = (-3/14)(7/3)

y = (-3 * 7) / (14 * 3)

y = -7 / 14

y = -1/2

4)

(z/3) + 2 = (z/5) + 1

since the two fractions are z/3 and z/5, the common denominator would be 15. Multiply everything by that...

15(z/3) + 15(2) = 15(z/5) + 15(1)

5z + 30 = 3z + 15

5z + 30 - 3z = 15

2z + 30 = 15

2z = 15 - 30

2z = -15

z = -15/2

Answer 4

1) to add numbers with fractions you need to find a common denominator for the fractions.  In this problem the two denominators are 13 and 39.  Since 39 is a multiple of 13 it can be the common denominator, so the problem becomes:

6 2/13      =  6 6/39

4            =  4

3 11/39   =  3 11/39

------------------------

               = 13 17/39

2) -5 3/5 / (-100)  change -5 3/5 and -100 to common fractions:

(-28/5) / (-100/1) the rule to divide one fraction by another is to invert the denominator and multiply so:

(-28/5) X (-1/100) = 28/500 = 7(4)/125(4) = 7/125

3) 3/7 y = -3/14 if this means 3y/7 = -3/14  using the axiom for a ratio of a/b = c/d that a X d = b X c meaning the cross products are equal we can derive that 3y(14) = 7(-3) ==> 42y = -21 dividing both sides by 42 ==> y = -21/42 and reducing ==> y = -1/2

check answer 3/7(-1/2) = -3/14 ==> -3/14 = -3/14

4) z/3 + 2 = z/5 + 1  we have two fractions one with denominator 3 and the other 5.  The common denominator for them is 3 X 5 = 15.  So multiply each side by 15 ==> 15(z/3 + 2) = 15(z/5 + 1) multiply through the parenthesis ==. 5z + 30 = 3z + 15  now subtract 3z from both sides and 30 from both sides

5z - 3z + 30 - 30 = 3z - 3z + 15 - 30 ==>

   2z = -15 divide both sides by 2 ==> z = -15/2 = -7.5

chech you answer back in the original equation

-7.5/3 + 2 = -7.5/5 + 1 ==> -2.5 + 2 = -1.5 + 1 ==>

-.5 = -.5 ==> correct answer  

Answer 5

-5 3/5 / (-100)

= (-28/5) / (-100)

= 28/500

= 7/125

3/7 y = -3/14

3y/7 = -3/14

3y(-14) = -3(7)

-42y = -21

y = -21/-42

y = 1/2

z/3 + 2 = z/5 + 1

z/3 - z/5 = 1 - 2

5z/15 - 3z/15 = -1

(5z-3z)/15 = -1

2z = -1(15)

z = -15/2

Answer 6

1. You need a common denominator for the fractions, which can be 39ths.  So, rewrite the fraction 6 2/13 (*3/3) as 6 6/39.  Then you have 6 6/39 + 4 + 3 11/39.

2. Dividing with fractions is the same as multiplying the reciprical.  So, you could rewrite this as -5 3/5 * -1/100.  Turn the mixed number -5 3/5 into an improper fraction -28/5.  Now you can easily multiply across the top and the bottom: -28/5 * -1/100.

3.  You need to get y alone by undoing the operation on the left side of the equal sign where y is.  Y is mutliplied by 3/7, so to undo it, do the opposite and divide both sides of the equal sign by 3/7.  On the left you'll have (3/7) / (3/7) * y, which equals y.  On the right you'll have (-3/14) / (3/7).  To finish remember dividing fractions is equivalent to myltiplying the reciprocal. That'll be y = (-3/14) * (7/3).  

4. Same ideas.  Get z alone by undoing operations and sort of working the equation backward.  Multiply both sides by 15 because that is a common denominator for the 3 and the 5.  You'll have 5z + 2 = 3z + 1.  Combine z's on one side and numbers on the other side.  Do opposite operations to "undo" and move them from side to side.  Your answer will be z = some fraction.

Answer 7

please be clear with ur question. not to gain just points but i didn't understand ur 1st 3 questions.

4)  z= -15/2

Answer 8

1st question:

= 6 2/3 + 4 + 3 11/39

= 20/3 + 4 + 128/39

= 260/39 + 156/39 + 128/39

= 544/39 or 13 37/39

Answer: 13 37/39

2nd question:

= (- 5 3/5)/(- 100)

= (- 28/5)/(- 100)

= 28/500 or 7/125

Answer: 7/125

3rd question:

3/7y = - 3/14

y = (- 3/14)/(3/7)

y = (- 3/14)(7/3)

y = ([- 3/3]/[14/7])([7/7]/[3/3])

y = - 1/2

Answer: y = - 1/2

4th question:

z/3 + 2 = z/5 + 1

5z + 30 = 3z + 15

2z = - 15

z = - 15/2 or - 7 1/2