Iwill give brainliest to whoever is correct

What is the y intercept of f(x)=(1/2)^x?

Solve the given system of equations. 2y= -x+9 , 3x-6= -15

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.