text: math question in high school adv. algebra ii? f(x)=2x+3 find a and b such that f(ax+b)=x f(ax+b) = 2(ax+b) + 3              = 2ax + (2b+3)  this equals x only if 2a=1, and 2b+3=0  then a = 1/2 and  b = -3/2