Question

1)-3/7+2/21 2)5/6+(-5/7) 3)-17/24+9/14 4)-3.91+3.91

Answer 1

1)-9/21+2/21=-7/21=-1/3
2)35/42-30/42=5/42
3)-119/168+108/168=-11/168
4)0

Answer 2

В первом и третьем ответы с "-"

Answer 3

Let's solve the given arithmetic expressions step by step:

1. (-3/7) + (2/21) To add these fractions, we need a common denominator. In this case, the common denominator is 21. Converting both fractions to have a denominator of 21:

(-3/7) * (3/3) = -9/21 (2/21) * (1/1) = 2/21

Now we can add the fractions:

-9/21 + 2/21 = (-9 + 2)/21 = -7/21 = -1/3

Therefore, (-3/7) + (2/21) equals -1/3.

2. (5/6) + (-5/7) To add these fractions, we need a common denominator. The least common multiple of 6 and 7 is 42. Converting both fractions to have a denominator of 42:

(5/6) * (7/7) = 35/42 (-5/7) * (6/6) = -30/42

Now we can add the fractions:

35/42 + (-30/42) = (35 - 30)/42 = 5/42

Therefore, (5/6) + (-5/7) equals 5/42.

3. (-17/24) + (9/14) To add these fractions, we need a common denominator. The least common multiple of 24 and 14 is 168. Converting both fractions to have a denominator of 168:

(-17/24) * (7/7) = -119/168 (9/14) * (12/12) = 108/168

Now we can add the fractions:

-119/168 + 108/168 = (-119 + 108)/168 = -11/168

Therefore, (-17/24) + (9/14) equals -11/168.

4. (-3.91) + (3.91) Adding these decimals is straightforward:

-3.91 + 3.91 = 0

Therefore, (-3.91) + (3.91) equals 0.