Answer:
y =20
Step-by-step explanation:
since this is an isosceles triangle <b= <c
<b =25 so < c =25
triangles add to 180
<a + <b + <c =180
<a + 25+25 = 180
<a + 50 = 180
subtract 50 from each side
<a = 130
3y+70 = 130
subtract 70 from each side
3y = 60
divide by 3
y =20
