Problem 1
The set below
{(-3,0), (13,4), (6, 3), (13, -4), (22, 5)}
is not a function. Focus on these two points (13,4) and (13,-4)
The input x = 13 leads to two different outputs y=4 and y = -4 at the same time. This is why we dont have a function. Any given input must point to exactly one output (assuming this input is in the domain of course)
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Problem 2
This is a function. It is impossible to draw a single vertical line through more than one point on the curve shown. This means the graph passes the vertical line test.
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Problem 3
y = -3x^2 + 10 is a function. Any input x leads to exactly one y output. The graph passes the vertical line test.