An isosceles triangle in which angles b and c have the same measure is shown. find the measure of each angle whose degree measure us represented with variables.

angle a: x+8y-1
angle b: 3y+4
angle c: 7x+5

We have 2 unknowns, therefore we have to set up two equations as well. The equations would be as follows:

180 = angle A + angle B + angle C
180 = x+8y-1 + 3y+4 + 7x+5 > Equation 1
8x + 11y = 172

B = C
3y+4 = 7x+5  > Equation 2
3y -7x = 1

x = 5
y = 12

Angle A: 100
Angle B: 40
Angle C:40