First observe the triangle, look at how the two sides are congruent. With that you can realize that the bottom right angle (3x+7) is congruent I the bottom left, meaning the bottom left angle is also 3x+7.
Next you would want to add 5x+13 to 3x+7 which will equal 180 because the two angles are on the same line and a line is 180 degrees. The equation would look like this after adding all like terms together: 8x+20=180. Next subtract 20 from both sides which will then look like 8x=160. Next isolate x by dividing by 8 on both sides to get x=20
True - since the outlier is way off it will cause your average to mess up which is why we test multiple times to make sure we are more accurate with our numbers
