standard_description: Explain why the sum or product of two rational numbers is rational; that the sum of a rational number and an irrational number is irrational; and that the product of a nonzero rational number and an irrational number is irrational.
problem_activity: Problem 1
Write the following as an imaginary number.
$${\sqrt{-72}}$$
Why is this not a complex number?
Problem 2
What kind of roots will the following quadratic function have?
$${4x-3x^2=10}$$


aligns: no