6. i. By HL postulate or RHS theorem
ii. 3x + 18 = 5x – 6
=> 18 + 6 = 5x – 3x
=> 12 = 2x
=> 12/2 = x
=> x = 6
Extra points :-
Types of angles - Corresponding angles.
12x + 3 = 11x + 9
=> 12x – 11x = 9 – 3
