Question

tolong soal 6,7,8,11,14 dengan cara jawab semua ya​
12poin

Answer 1

Jawab:

Penjelasan dengan langkah-langkah:

fungsi

soal 6

f(x) = 2x² + 5x- 7

gx) =3x- 12

gof(2) = g { f(2)}

= 3. f(2) - 12

= 3 { 2. 2² + 5(2) - 7 ) - 12

= 3 (8 + 10 - 7) - 12

= 3(11) - 12

= 33- 12

= 21

soal 7

f(x) =  x - 3

g(x)= x² + 2x

gof(x) =  g { f(x)}

= f² (x) + 2  f(x)

= (x - 3)² + 2 ( x- 3)

= x² -6x + 9 + 2x -  6

= x² - 4x +  3

soal 8

f(x) =  3x² +10x - 8

g(x) =  2x - 1

fog(x)=  f {g(x)}

= 3.g²(x) + 10  g(x) - 8

= 3 (2x- 1)² + 10 (2x- 1) - 8

= 3 (4x² - 4x + 1) + 20x -10 - 8

= 12x² -12x + 3 + 20 x    - 10 - 8

= 12x² + 8x - 15

soal 11

f(x) = 2x+ 3 --> f(-2) = 2(-2) + 3

f(-2) = -1

g(x)= 3x² -2x + 5

gof(-2) =  g{ f(-2)}

= 3. f²(-2) - 2  f(-2) + 5

= 3 (-1)² - 2 (-1) + 5

=  3 + 2 + 5

= 10

soal 14

fog(x) = 4x² + 8x - 3

g(x)=  2x+ 4

f (2x + 4) = 4x² +8x - 3

f(-2) = ...

2x + 4 = -2

2x= 6

x=  3

f(-2) =  4(-3)² +8(-3) - 3

f(-2) =36 -24 - 3

f(-2) = 9