Can anybody help me with understanding how to do -2+a/3 = -4?

Angle xyz is formed by segments xy and yz on the coordinate grid below: a coordinate plane is shown. angle xyz has endpoints at 3 comma negative 1 and 6 negative 2 and 3 comma negative 3 and measures 36.87 degrees. angle xyz is rotated 270 degrees counterclockwise about the origin to form angle x′y′z′. which statement shows the measure of angle x′y′z′?

Tan198=asin164=? how to solve this? ?

When i'm with my factor 5, my prodect is 20 .when i'm with my addend 6' my sum is 10.what number am i