6x-18
you pretty much h just multiply both the first part of the parentheses by the number outside, then the second :)
Angle 4 is 77 degrees. Since angles 1, 2, and 3 must add up to 180 degrees, and angles 3 and 4 must also add up to 180 degrees, angles 1 + 2 must be equal to angle 4
D the argument is not valid because the conclusion does not follow from the premises
