If $f (x) = x^{2} + 3 x$ $f(x) = x^2 + 3x$ and $g (x) = 4 x - 1$ $g(x) = 4x - 1$ , what is $(g \circ f) (- 3)$ $(g@f)(-3)$ ?

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Answer 1 · 2015-09-13T13:44:46

It is $- 1$ $-1$

First since both functions are polynomials their composition can be defined.

$g (f (x)) = 4 (x^{2} + 3 x) - 1 = 4 x^{2} + 12 x - 1$ $g(f(x))=4(x^2+3x)-1=4x^2+12x-1$

Hence the value $g (f (- 3)) = 4 \cdot {(- 3)}^{2} + 12 \cdot (- 3) - 1 = - 1$ $g(f(-3))=4*(-3)^2+12*(-3)-1=-1$

If f(x)=x2+3xf(x) = x^2 + 3x and g(x)=4x−1g(x) = 4x - 1, what is (g∘f)(−3)(g@f)(-3)?