I plotted for all real number as a diagonal line on x-y axis and then plotted . By plotting , I have made sure none of the real number y is excluded. I found that all is possible on the diagonal line, but for x, I found it a very different story, namely, approaches neither of the axes--neither x nor y, which means that if , neither nor can be a zero.

Since the statement says , we choose any then find ; in other words, by choosing any x then find y would makes no sense.

If you take , you need not stick to because it did not say for all . Since means at least one, I do have one, namely x=1/2.

At any rate, it's very nice of you to help me. I enjoy reading many of you posts. You are quite good at math.