the 3 angles of a triangle must add to 180. always. since one of our angles (c) is given as 90 already, the other 2 must add too 180-90, or 90. the 2 angles are 48-x and 9x-38, which Sim to 8x+10. if 8x+10=90, then x=10 (I assume you are ok with the algebra). then a=38 and b=52