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For all values of x, f(x)=2x^2 and g(x)= x+1
Solve fg(x) = gf(x)


Sagot :

Answer:

-0.25

Step-by-step explanation:

→ Find fg(x)

2 ( x + 1 )² = 2x² + 4x + 2

→ Find gf(x)

2x² + 1

→ Equate them

2x² + 1 = 2x² + 4x+ 2

→ Move everything to the right hand side

0 = 4x + 1

→ Solve

x = -0.25

Answer:

[tex]-\frac{1}{4}[/tex]

Step-by-step explanation:

Work out fg(x)

To work out fg(x), put the g function into the f function so, the x in f(x) is equal to the x+1 (from the g function) so:

[tex]2(x+1)^{2} = 2 (x^{2} +2x+1) = 2x^{2} + 4x +2[/tex]

So fg(x) = [tex]2x^{2} + 4x +2[/tex]

Work out gf(x)

Do this by substituting the f(x) equation into the g(x) which is:

[tex](2x^{2} )+1[/tex]

So gf(x) = [tex](2x^{2} )+1[/tex]

Work out x

And since fg(x) = gf(x),

[tex]2x^{2} + 4x +2[/tex] = [tex](2x^{2} )+1[/tex]

4x = -1

x =[tex]-\frac{1}{4}[/tex]