## haloom1 2 years ago what is -5/11--5/7

1. unkabogable

is it: |dw:1352573819063:dw|

2. haloom1

thank you, please can you explain

3. amorfide

first of all you have a double negative these change to a plus sign

4. amorfide

next you want to get the same denominator to do this |dw:1354103093726:dw|

5. amorfide

|dw:1354103213183:dw|basically the fish type thing represents what is being multiplied so for example lets say we have two fractions a/b + c/d |dw:1354103176755:dw| to add them the general method is to do (ad +bc)/bd

6. amorfide

do you understand?

7. zordoloom

You would have to find a common denominator first.

8. zordoloom

Do you still need help?

9. amorfide

following the method I explained gives a common denominator @zordoloom

10. jazy

|dw:1354106538781:dw|$-\frac{ 5}{ 11 } + \frac{ 5 }{ 7 }$Find a least common factor of 7 & 11 to find the LCD. Factors of 11: 11, 22, 33, 44, 55, 66, 77 Factors of 7: 7, 14, 21, 28, 35, 42, 49, 56, 63, 70, 77 Least common factor is 77. 11 times 7 = 77 so multiply both the numerator and denominator by 7. $\frac{ -5 }{ 11 } \times7 = -\frac{35 }{77 }$ 7 times 11 = 77 so multiply both the numerator and denominator by 11. $\frac{ 5 }{ 7 } \times 11 = \frac{ 55 }{ 77 }$ NOW you can add the fractions: $-\frac{ 35 }{ 77 } + \frac{ 55 }{ 77 } = \frac{ (-35 + 55) }{ 77 } = \frac{ 20 }{ 77 }$ So: $-\frac{ 5}{ 11 } + \frac{ 5 }{ 7 }\ =\frac{ 20 }{ 77 }$

11. jazy

@haloom1