Respuesta :

Answer:

A = 20

Step-by-step explanation:

A + 71x - 1 = 90o That's because all triangles have 180 degrees.

71x - 1 + 20x = 90        Combine like terms.

91x - 1 = 90                  Add 1 to both sides.

91x - 1 + 1 = 90 + 1        Combine

91x = 91                       Divide by 91

91x/91 = 91/91

x = 1

Angle A = 20x

Angle A = 20*1

Angle A = 20