Answer:
x =  5. 
First angle = 20°,  Second angle = 85°,  Third angle  = 75° 
Step-by-step explanation:
The first angle of the triangle  =  (4 x)
The second  angle of the triangle  =  (6x + 55)
The third angle of the triangle  =  (9x + 30)
By ANGLE SUM PROPERTY of a triangle: 
 First angle + Second  angle +  Third angle  = 180°
⇒ (4 x)  + (6x+55)   +  (9x+30)  = 180°
or, (4x + 6x + 9x) + ( 55 + 30) =  180°
or, 19x = 180 - 85
or, 19 x  = 95   ⇒ x = 95 /19 = 5
or, x = 5
Hence, first angle of the triangle  =  (4 x) = 4 x 5 = 20°
Second angle = ( 6x + 30)  = 6(5) + 55 = 85°
Third angle = (9x  + 30  = 9(5) + 30 = 75°