Simplify: -4 over 5 + 3 over 4?

Find the LCM (least common multiple) of 5 and 4.
5 = ...........5
4 = 2 x 2
-----------------------
...= 2 x 2 x 5
...= 20

-4/5 + 3/4
= (-4 * 4)/(5 * 4) + (3 * 5)/(4 * 5)
= -16/20 + 15/20
= -1/20
(answer A)

- 4/5 + 3/4 =
- 16/20 + 15/20 =
- 1/20.

A. is correct.

the answer is A -1 over 20//

A. -1 over 20

A

- 4
---------------
8
-----
4

- 16
-------
8

- 2

But this is NOT what you mean !

You mean :-

- 4 / 5 + 3 / 4

- 16 / 20 + 15 / 20

- 1 / 20

OPTION A

-4/5=-16/20+11520= -1/20 A

first get a common denominator and then do simple addition. You end up with
-16/20 + 15/20 = -1/20.

Look for a common denominator, in this case, the common denominator for 5 and 4 is 20

so -4 over 5 is also -16 over 20
and 3 over 4 is also 15 over 20

Now that you have a common denominator for both, just compute for the numerator.

-16 over 20 + 15 over 20 = -1 over 20

A

change both to have 20 in bottom line ie

-16 / 20 and 15 / 20