How to simplify, assuming all variables are nonnegative?
Please help!

Write numerical coefficient of y² in the expression 2x² - 15xy – 7y²

Hundred and tens tables to make 430 in five different ways

Is the response to the survey question "did you smoke in the last week question mark "response to the survey question "did you smoke in the last week? " a discrete random variable, a continuous random variable, or not a random variable?