Q1. Prove the following statement: for all integers a and b, if a is even and b is a multiple of 3, then ab is a multiple of 6. Q2. If m and n are integers and neither m nor n is zero, is (m n)/mn a rational number? Q3. Use proof by contradiction to show that the sum of any rational number and any irrational number is irrational. Hint: You can use the following definition to assist you answer Q1 and Q2 Definition: A real number ris rational if, and only if, it can be expressed as a quotient of two integers with a nonzero denominator. A real number that is not rational is irrational. More formally, if ris a real number, then ris rational eointegers a and b such that r= and bz 0