I need help please. Please

What signals you that factoring by grouping is the best method to use when factoring a problem?

What are the solutions of the system? solve by graphing. y = x^2 + 3x + 2 y = 2x + 2

Is the product of two rational numbers irrational or rational? first, make a hypothesis by multiplying two rational numbers. then, use variables such as x=a/b and y=c/d and the closure property of integers to prove your hypothesis.