Help me please---I'm so confused right now

What is the effect on the graph of the parent function f(x) = x when f(x) is replaced with 3f(x)? a) shifts the line 3 units up b) shifts the line 3 units down c) increases the slope of the line by a factor of 3 d) decreases the slope of the line by a factor of 3

The system of equations graphed below has how many solutions? y = 2x + 2

Determine the relationship of ab and cd given the following points