A multiplier on the function value moves its y-coordinate farther from the x-axis by that multiplier value. It is the stretch factor. Stretch factors less than 1 cause the graph to be compressed vertically.
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A multiplier on the independent variable means it doesn't need to be as large to give the same function value. That is, multiplication of x by a factor of k compresses the graph horizontally by that factor of k. Equivalently, it does a horizontal stretch by a factor of 1/k.