Answer:
a. x=11°
b. ABC=106°, BCA=33° and BAC=41°
c. Sorry but I can't see the lines l and m
Explanation:
a. the question stated that the sum of the measures of the angles in the triangle is 180°
so therefore equate all the values in the triangle to 180°
(9x+7)+ 3(x) + (3x+8)=180°
15x+ 15=180
15x=180-15
15x=165
Divide both sides by 15
therefore x=11
b. ABC=(9x+7)
where there is x put the x value you solved for there which is 11
therefore ABC=(9×11+7)= 106°
Do the same for BCA and BAC