20 point❣ bantuin kerja nomor 39 dan 40 beserta jalannya

k(x) = x + 3
jok(x) = x² - 4

maka
x² - 4
= x² + 6x + 9 - 6x - 18 + 5
= (x + 3)² - 6(x + 3) + 5
jadi
j(x) = x² - 6x + 5

j(x - 2) = (x - 2)² - 6(x - 2) + 5
           = x² - 4x + 4 - 6x + 12 + 5
           = x² - 10x + 21

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g(x) = 2x + 3
fog(x) = 12x² + 32x + 26
maka
12x² + 32x + 26
= 12x² + 36x + 27 - 4x - 6 + 5
= 3(4x² + 12x + 9) - 2(2x + 3) + 5
= 3(2x + 3)² - 2(2x + 3) + 5

jadi f(x) = 3x² - 2x + 5