Question

1. which graph shows a function? (images of graphs a, b, c, d are present)

Explanation:

Step1: Recall Vertical Line Test

A graph represents a function if no vertical line intersects it more than once.

Step2: Analyze Graph A

For graph A, any vertical line will intersect it at most once (it's a horizontal line), so it passes the vertical line test.

Step3: Analyze Graph B

Graph B has two lines intersecting (like an "X"), so a vertical line through the intersection point would intersect twice, failing the test.

Step4: Analyze Graph C

Graph C is a parabola opening downward, but wait, no—wait, actually, looking at the sketch, if it's a vertical parabola? No, wait, the graph C seems to have a vertical line of symmetry, but actually, no—wait, no, the key is vertical line test. Wait, no, graph C: if it's a parabola opening left or right? Wait, the original graph: the user's image. Wait, no, the first graph (A) is horizontal, B is two crossing lines, C is a U - shaped but maybe horizontal? Wait, no, the standard vertical line test: for a function, each x has one y. So graph A: horizontal line, so for any x, y is constant—passes. Graph B: two lines (like y = x and y=-x), so for x = 0, two y's—fails. Graph C: if it's a vertical parabola (opening up/down), it's a function, but wait the sketch: maybe C is a horizontal parabola (opening left/right), which would fail. Wait, the user's image: Graph A is a horizontal line, B is two intersecting lines (like cross), C is a U - shaped but maybe horizontal (so vertical line would intersect twice), D is a square - like? Wait, no, the initial analysis: Graph A: horizontal line, so vertical line test: any vertical line cuts it once. So Graph A passes.

Step5: Analyze Graph D

Graph D (the square - like) would have vertical lines intersecting twice, so fails.

Answer:

A (the graph labeled A)