At what point does the graph of the line y=2x−6 cross the y-axis? (2, −6)
(0, 2)
(0, −6)
I don't know.

What is the value of x when x + 7 = 21?

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.

If sin(x) = 0 and cos(x) = 1, what is tan(x)?