see below (I hope this helps!)
Step-by-step explanation:
41. √20 = √4 * 5 = √4 * √5 = 2√5
43. The sum of interior angles in a triangle is 180°, therefore, x = 180 - (75 + 64) = 41°.
45. 15 + 5(2x - 3) = 15 + 5(2x) + 5(-3) = 15 + 10x - 15 = 10x
47. Complementary angles have a sum of 90°, therefore, x = 90 - 48 = 42°.