You can put this solution on YOUR website! A function can be described by various graphs with multiple curves or changes of direction.
A linear function describes only a straight line, so the highest exponent is 1.
A function can have exponents as high as needed.
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The following are graphs of;
y = x, a linear function (red)
y = x^2, a non-linear function (green)
y = x^3, a non-linear function (blue)
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