Diketahui $f(x)=3-x$, $g(x)=x^2+2x-5$, dan $h(x)=2x+1$. Nilai$(g\circ h\circ f)(2)=\dots$
A. 5
B. 10
C. 15
D. 20
E. 25
Penyelesaian
Diketahui:
$f(x)=3-x$
$g(x)=x^2+2x-5$
$h(x)=2x+1$
Ditanya:
$(g\circ h \circ f)(2)=?$
Jawab
$g(x)=x^2+2x-5$
$(g\circ h)(x)=(2x+1)^2+2(2x+1)-5$
$(g\circ h)(x)=4x^2+4x+1+4x+2-5$
$(g \circ h)(X)=4x^2+8x-2$
$(g \circ h \circ f)(x)=4(3-x)^2+8(3-x)-2$
$(g \circ h \circ f)(x)=4(9-6x+x^2)+24-8x-2 $
$(g \circ h \circ f)(x)=36-24x+4x^2+24-8x-2$
$(g \circ h \circ f)(x)=4x^2-32x+58$
$(g \circ h \circ f)(2)=4(2)^2-32(2)+58$
$(g \circ h \circ f)(2)=16-64+58=10$
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