Respuesta :

Since it's an isosceles triangle, their base angles must be equal.
5x + 6 = 8x - 15
21 = 3x
x = 7

Now substitute those values in and subtract them from 180 to find Y.
5(7) + 6 = 8(7) - 25
35 + 6 = 56 -25
41 = 41

180-41-41 = 98

Y= 98 degrees
5x + 6 = 8x - 15
21 = 3x
x = 7
5(7)=35+6=41
8(7)=56-15=41
41+41=82
180-82=98