Question

Is y=3x^3+4x^2+15x+7 a function and if it is, explain

Answer 1

Answer: Yes it is a function.

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Step-by-step explanation:

It is a function because any x input leads to exactly one y output. The graph visually passes the vertical line test. It is impossible to draw a single vertical line through more than one point on the cubic curve, so that's why the graph passes the test, and visually confirms we have a function.

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Extra info:

Something that isn't a function is
`y^2 = x` because it graphs a sideways parabola in which it is possible to draw a vertical line through more than one point on the curve. Two points on this parabola are (9, 3) and (9, -3). The input x = 9 corresponds to more than one output y = 3 and y = -3 simultaneously.