Answer:
86°
Explanation:
Given:
A = (6x + 10)°
B = (4x +30)°
Two angles are supplementary if they sum up to 180° ;
A + B = 180°
Now insert the parameters and solve;
6x + 10 + 4x +30 = 180
10x + 40 = 180
10x = 140
x = 14
So;
B = (4x +30)° = 4(14) + 30 = 86°