If 136 is the area and 136=3x^2+10x=x(3x+10)=(1/2)(base)(height), then (base)(height)=272.
Also, if 3x^2+10x=136 then 3x^2+10x-136=0; (3x+34)(x-8)=0, making x=8 or -34/3. So 3x+10=34 or -24. The negative values can be dropped as meaningless. The base and height are interchangeable, so we have (base or height, height or base)=(8,34).