# Free Compass Math Practice on Complex Numbers Sample 23

 A set of questions, with answers, on complex numbers are presented. These questions are similar to those in the compass math test and their answers are at the bottom of the page. For i = √-1 and if - 2 i (3 - 5i) = - 10 + x i, then x =? A) 6 B) - 10 C) - 6 D) 10 E) 0 For i = √-1, (3 - i)(3 - 5i) =? A) 4 B) 9 - 5 i C) - 4 i D) 14 - 18 i E) 4 - 18 i For i = √-1, (-2 + i) / (1 - i) =? A) 2 - i B) - 3 / 2 - i / 2 C) 1 / 2 - i / 2 D) - 1 / 2 - i / 2 E) 3 / 2 + i / 2 For i = √-1, i147 =? A) 0 B) 1 C) - 1 D) i E) - i For i = √-1, i22 + i23 =? A) - 1 - i B) 1 + i C) i D) 2 i E) 0 For i = √-1, (-i)103 =? A) 0 B) 1 C) - 1 D) - i E) i For i = √-1, if (8 - 4 i) / (- 2 + 2i) = a + b i, where a and b are real numbers, then b =? A) -2 B) 2 C) - 1 D) 1 E) 0 w and z are two complex numbers given by w = -2 + 5 i and z = 1 - 3 i where i = √-1. Find 2 w + 3 z. A) - 1 + 2 i B) 1 - i C) - 1 - i D) - 1 + i E) 2 + i For i = √-1, (2 - 3 i )2 =? A) 4 - 9 i B) - 5 - 12 i C) 4 + 9 i D) 5 + 12 i E) 13 For i = √-1, 2 (3 - 4 i) - i (2 - i) =? A) 5 - 10 i B) 5 + 10 i C) 6 - 2 i D) 4 - 7 i E) - 5 - 10 i For i2 = -1 where i is the imaginary unit, i + i2 + i2 + ... + i77 =? A) - i B) 1 C) i D) - 1 E) 0