Answer:
x = 6
Step-by-step explanation:
The three angles form a straight line, which is 180 degrees
5x+ (x+54) +90= 180
Combine like terms
6x+144 = 180
Subtract 144 from each side
6x+144-144 =180-144
6x =36
Divide each side by 6
6x/6 = 36/6
