PLZ HELP ME IT'S PRE-CAL THANKS IN ADVANCE

Question

State whether the following solution sets are from a function or non-function

1. y=x²
2. y²=4-x²
3. y=x³
4. y=±√1-2x

Answer 1

You need to apply the vertical line test to plots of each of these equations. If a vertical line intersects the curve more than once, then the equation is not a function.

1) Is a vertical parabola. Line intersects the parabola only once, not matter where it is placed along the x-axis.

Is a function.

2) A circle. Not a function because a vertical line will intersect the circle twice.

3) A cubic. A function, only one intersection with a vertical line.

4) Since ± is given, this is a horizontal parabola and a non-function since a vertical line will intersect the parabola above the x-axis and below the x-axis.

Answer 2

1. yes
2. no
3. yes
4. no