PEMDAS states that the value in the parenthesis should be evaluated first: 4(5*6) 4(30) After just multiply the value in the parenthesis by the number outside of the parenthesis: 120
Both lines are parallel so using the bottom line you are given angle 7 as being 80 degrees. Angle 5 and 7 form a straight line which is 180 degrees so angle 5 would be 180-80 = 100 degrees.
Angle 1 is the same as angle 5 so angle 1 is 100 degrees.