Question

Δ ABC is isosceles. If m∠A = 100°, m∠B = (12x + 4)°, and m∠C = (14x - 2)°, find x.

Answer 1

12x + 4 + 14x - 2 + 100 = 180
26x + 102 = 180
26x = 78
x = 3

or you can do
12x + 4 = 14x - 2 (because Δ ABC is isosceles)2x = 6
x = 3

Answer 2

I am trying to imagine this and it sounds like the two base angles, which are equal, are (12x+4) and (14x-2). And since this is a triangle the sum of these two angles must be 180-100=80°

12x+4+14x-2=80

26x+2=80

26x=78

x=3

Since we know that they are equal we could also just have said:

12x+4=14x-2

-2x=-6

x=3

:P