9) Find 4ab when a + b = 15 and a - b = 3
(A) 18
(B) 24
(C) 234
(D) 216
10) Simplify x/15 * 9/y
(A) 3x/5y
(B) 5x/3y
(C) 9x/15y
(D) x/y
11) Simplify a2/2 ÷ a3/4
(A) a/2
(B) a6/8
(C) 4a2/2a3
(D) 2/a
12) Find the value of a2 - b2/(a-b), when a = 2.9 and b = 9.1
(A) 122
(B) 92
(C) 12
(D) 25
13) What is the value of a and b, If a2 - b2 = 36 and a + b = 6
(A) a = 9, b = 9
(B) a = 6, b = 0
(C) a = 0, b = 6
(D) a = 3, b = 15
14) Find the value of xy, when x2 + y2 = 58 and x2 - y2 = 42
(A) 10
(B) 12
(C) 15
(D) 20
15) If x = 235 and y = 117, then x2 - y2/x - y = ?
(A) 118
(B) 100
(C) 115
(D) 352
16) If x2 - y2 = 16 and x2 + y2 = 34, which of the following could be the value of xy?
I 15
II -15
III 45
(A) only I
(B) only II
(C) I and II only
(D) III only