I'm sorry for this, but what is the range and domain of the following function? y = 24 - 2x y has to be positive (y > 0) and x too (x > 0) How would you solve this? Do you just need a look and then be able to write it down? Or do you need to solve it with algebra? I've found that x can only be up to 12, or else y would be negative: y = 24 - 2x 0 = 24 - 2x x = 12 What is then the minimum of x? 2x = 24 - y 0 = 24 - y y = 24 When y is 24, x is zero. This means: 0 < x < 12 With these values, y is always positive, we have solved the domain of the function. Is this correct?