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Given that f(x) = 6x - 5 g(x) = 3x + 4 and h(x) = 4x – 6

2

Find:-

i) g(-2) = ii) g[h(x)] = iii) f[g(2)] =




iv) gᴏh(2) vi) h-1(11

Answer :

Answer:

(i) [tex]g(-2)=-2[/tex]

(ii) [tex]g[h(x)]=12x-14[/tex]

(iii) [tex]f[g(2)]=55[/tex]

(iv) [tex](g\circ h)(2)=10[/tex]

(v) [tex]h^{-1}(11)=\frac{17}{4}[/tex]

Step-by-step explanation:

The given functions are

[tex]f(x)=6x-5[/tex]

[tex]g(x)=3x+4[/tex]

[tex]h(x)=4x-6[/tex]

(i) Find g(-2).

Substitute x=-2 in g(x).

[tex]g(-2)=3(-2)+4\Rightarrow -6+4=-2[/tex]

(ii) Find g[h(x)]

[tex]g[h(x)]=g(4x-6)[/tex]                 [tex](h(x)=4x-6)[/tex]

[tex]g[h(x)]=3(4x-6)+4[/tex]           [tex](g(x)=3x+4)[/tex]

[tex]g[h(x)]=12x-18+4[/tex]

[tex]g[h(x)]=12x-14[/tex]

(iii) Find f[g(2)].

[tex]f[g(2)]=f[3(2)+4][/tex]           [tex](g(x)=3x+4)[/tex]

[tex]f[g(2)]=f(6+4)[/tex]

[tex]f[g(2)]=f(10)[/tex]

[tex]f[g(2)]=6(10)-5[/tex]           [tex]f(x)=6x-5[/tex]

[tex]f[g(2)]=55[/tex]

iv) Find gᴏh(2).

[tex](g\circ h)(2)=g[h(2)][/tex]

[tex](g\circ h)(2)=12(2)-14[/tex]           (From part (ii) we get [tex] g[h(x)]=12x-14)[/tex]

[tex](g\circ h)(2)=10[/tex]

(v) Find [tex]h^{-1}(11)[/tex]

First find [tex]h^{-1}(x)[/tex].

[tex]h(x)=4x-6[/tex]

[tex]y=4x-6[/tex]

[tex]x=4y-6[/tex]

[tex]x+6=4y[/tex]

Divide both sides by 4.

[tex]\frac{x+6}{4}=y[/tex]

[tex]h^{-1}(x)=\frac{x+6}{4}[/tex]

Substitute x=11 in the inverse function.

[tex]h^{-1}(11)=\frac{11+6}{4}[/tex]

[tex]h^{-1}(11)=\frac{17}{4}[/tex]

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