a triangle has 55 degrees interior angle, one 3x+2 interior angle, and one 13x-3 exterior angle and the rest of the 180 degrees is unknown. what is x?
I assume we are using the Exterior Angle Theorem here....if so, we have
13x - 3 = [ 3x + 2] + 55 simplify
13x - 3 = 3x + 57 add 3 to both sides, subtract 3x from both sides
10x = 60 divide both sides by 10
x = 6 [degrees]
