Hey
These are my answers and the explanations
Question 1.
Anwer : 1 (Statement 1 is sufficient)

angle ABC = 180 - (angle BAC + angle ACB)
angle ABC = 180 - 3x

angle DBC = 180 - (ang BDC + and DCB) = 180 - 4x

ang DBA = ang ABC - ang DBC
ang DBA = (180 - 3x) - (180 - 4x) = x

ang BAC = ang DBA, therefore length of AD = length of BD

ang BDC = ang DCB, therefore length of CD = length of BD.

so length of AD = length of BD = length of CD
so option 1 alone is enough

Option 2 tells about value of x, but that doesnt tell anything abt the length.



Question 2:
Answer : Optoin 5

Explanation
Option 1 says (a + b)^2 = a^2 + b^2 . this is wrong
option 2 : (a + b ) + 1 = (a + 1) + (b + 1)
a + b + 1 = a +b+2
this is also wrong

opoin 3: square root(a+b) = square root(a) + square root(b)
this is also wrong

option 4: 2/(a+b) = 2/a + 2/b
This is also wrong (put a=1 and b=1, you will see it is wrong)

option5 :
-3 * (a + b) = (-3 * a) + (-3 * b)
-3a -3b = -3a -3b
So this is correct


Hopefully this helps