How to I prove DAC ≈ BCA

What is the inverse of the function f(x) = 2x + 1?

Achemist has 200 ml of a 10% sucrose solution. she adds x ml of a 40% sucrose solution. the percent concentration, y, of the final mixture is given by the rational function: the chemist needs the concentration of the final mixture to be 30%. how many milliliters of the 40% solution should she add to the 10% solution to get this concentration?

On a piece of paper, graph y< x+1. then determine which answer matches the graph you drew.