Iwill award ,
in equilateral △abc, y =

a. 90°

b. 70°

c. 60°

d. 45°

B. 70°

Step-by-step explanation:

If this is an equilateral triangle, then each angle is   180/3 = 60

<A = 60 = x+3x+2x

      60 = 6x

     60/6 = 6x/6

  10 =x

Angle B will also equal 60 degrees

BDA  + x + B = 180

BDA + 10 + 60 = 180

BDA + 70 = 180

BDA = 180-70

BDA = 110

BDA  and y are complementary angles since they form a straight line

BDA + y = 180

110 +y =1 80

y = 180-110

y = 70