Question

what what number should be added to - 1 so as to get 5 by 7

Answer 1

additive inverse of 2/5 is -2/5

Therefore, 4/7 - 2/5 = 4/7 + (-2/5)

⇒ 4/7 - 2/5 = 4 × 5/7 × 5 + (-2) × 7/5 × 7

                = 20/35 + -14/35

                = 20 + (-14)/35

                = 6/35

Therefore, 4/7 - 2/5 = 6/35


2. Subtract -6/7 from -5/8.

Solution:

The additive inverse of -6/7 is 6/7

Therefore, -5/8 - (-6/7) = -5/8 + 6/7, [Since, -(-6/7) = 6/7)]

⇒ -5/8 - (-6/7) = -5 × 7/8 × 7 + 6 × 8/7 × 8

⇒ -5/8 - (-6/7) = -35/56 + 48/56

⇒ -5/8 - (-6/7) = -35 + 48/56

⇒ -5/8 - (-6/7) = 13/56

Therefore, -5/8 - (-6/7) = 13/56

 

3. Subtract -4/9 from 2/5

Solution:

The additive inverse of -4/9 is 4/9.

Therefore, 2/5 - (-4/9) = 2/5 + 4/9, [Since, -(-4/9) = 4/9)]

⇒ 2/5 - (-4/9) = 2 × 9/5 × 9 + 4 × 5/9 × 5

⇒ 2/5 - (-4/9) = 18/45 + 20/45

⇒ 2/5 - (-4/9) = 18 + 20/45

 Therefore, 2/5 - (-4/9) = 38/45


4. The sum of two rational numbers is -3/5. If one of the number is -9/20, find the other.

Solution:

Sum other number = -3/5, One number = -9/20

Therefore, the other number = Sum of the two rational numbers - One of the given rational number.

                                       = -3/5 - (-9/20)

                                       = -3/5 + 9/20, [Since - (-9/20) = 9/20]

                                       = (-3) × 4 + 9 × 1/20

                                       = -12 + 9/20

                                       = -3/20

Answer 2

Hey mate........ here's your answer....

Actually it's not possible according to the Maths.
Hope it helps*****