What is the value of y? enter your answer in the box. Y = an isosceles triangle a b c. Side b c is the base. Sides a b and a c are equal. Sides a b and a c are labeled with single tick marks. Angle a is labeled as left parenthesis 2 y plus 20 right parenthesis degrees, angle b is labeled as left parenthesis 5 x right parenthesis degrees, and angle c is labeled as 40 degrees.