If f (x) = 4x^2 and g (x) = 5x, what is g (f (2x)) ?

f (x) = 4x²

g (x) = 5x

first let us find f (2x)

replacing x by 2x in f (x)

f (2x) = 4 (2x) ² = 4 (4x²) = 16x²

now we find g (f (2x))

we plug the value of f (2x) which is 16x² in the function g (x)

g (f (2x)) = g (16x²) = 5 * 16x² = 80x²

So g (f (2x)) = 80x²