The product of a non-zero rational number and an irrational number is irrational.
Therefore C is the answer.
A, B, and D are all properties of rational numbers. Irrational numbers are ones that can not be written as a ratio, or fraction, using whole numbers. They are non-repeating, non-terminating numbers. Example would be pi.
Answer: B
Begin by simplifying the given equation, so it's rearranged into standard form. Move all the terms onto one side, so they equal 0. This would result with 
-3x-9=0. Quadratic formula is (-b±√(b²-4ac))/(2a). Standard form follow this variable format: 
+bx+c. Use the numbers that correspond with each variable to substitute them into the quadratic formula. This would be
(-(-3)±√(-3²-4(4)(-9)/2(4).
