20. (a) In the given figure, AB is a diameter. The tangent at C meets AB produced at Q. If ∠CAB = 34°, find :- (i) ∠CBA   21. (ii) ∠CQA (Type in the answers separated by commas. Leave no spaces around the commas.)   22. (b) If the lines y = 3x + 7 and 2y + px = 3 are perpendicular to each other, find the value of p. (Leave no spaces in your answer.)   23. (c) Let A = [ 4 −2 6 −3 ] , B = [ 0 2 1 −1 ] and C = [ −2 3 1 −1 ] Find A2 − A + BC.