Supplementary angles are angles that add up to 180 degrees.
180 = 3x + 4 + 8x + 11
Combine like terms.
180 = 11x + 15
Subtract 15 from both sides.
165 = 11x
Divide both sides by 11
15 = x
m<ABC = 3x + 4 = 3(15) + 4 = 45 + 4 = 49 degrees.
Sorry, I'm not sure.
I would suggest asking a trusted adult or teacher or redoing the lesson. Cheating isn't a good path: you will not do well in the future if you always search for answers on the internet.
7x-4=52 is correct because he made 7 times more than Jack which is 7x. For example if Jack made 8 decorations, 7 x (8) = 56. If you subtract 4 from 56 you get 52. Therefore, the equation 7x-4=52 is correct.
