D, Because 7/15 + 9/15 is 16/15 + 4/15 =20/15 which equals 1 5/15 which turns into 1 1/3
A, 1/21 + 2/21 = 3/21 and that equals 1/7
C, 3/14+3/12 turns into 3/14+5/14= 10/14 - 8/14= 2/14=1/7
Answer:

Option (C) is correct .
Step-by-step explanation:
As the expression given in the question as follows.

Now rationalize the expression.

Using the formula
a² - b² = (a - b) (a + b)
Using in the above


As i² = -1



Option (C) is correct .
Answer:
ANSWER is B. look at the sides and simplified.
Answer:
Step-by-step explanation:
<u>Sum of interior angles of any triangle is 180°:</u>
- 52° + 43° + x = 180°
- 95° + x = 180°
- x = 180° - 95°
- x = 85°
Answer: The first one
Step-by-step explanation: first you have to subtract 5 from both sides and then you have -6n < 6 . Then you have to divide both sides by -6 then you get n < -1.