Answer:
1st question: x = 17
2nd question: ∠A = 66°
Explanation:
1st question-
all angles of a triangle adds up to 180. so,
(6x + 10) + (x + 17) + (4x - 34) = 180
6x + x + 4x + 10 + 17 - 34 = 180
11x -7 = 180
11x = 187
x = 187/11
x = 17
2nd question-
in an isosceles triangle, 2 of its angle are the same
here, ∠C & ∠B are equal
so,
180 - (57+57)
= 66°