True, False or Uncertain; explain your answer. When income rises and the price of x falls, the consumer will always buy more units of x.

False. In the case of income rising and the price falling for a standard (non-Giffen) inferior good, then the effects will be in opposite directions; the income rise will tend to cause fewer units to be purchased, but the price fall will tend to induce more units to be purchased. We can't say what the net effect is without knowing more about the magnitude of the changes and the consumer's preferences. In general, when making predictions using economic theory, it is best to change only one parameter at a time.

question 1: I have failed to understand the answer, please explain

question 2: what happens if it was for a giffen good?