A stretch by a factor of 2 for the exponential growth function f(x)= a (nine-fourths) Superscript x [image 1] occurs when a =[___].

In f(x) = a(9/4)^x, the coefficient a controls the vertical stretch. A stretch by a factor of 2 means multiplying the function’s values by 2, so a = 2. The correct choice is 2.

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