tolong babtu nomor 7 sama 10 makasi

No 7

f(x) dibagi x²-x-2 misal sisanya ax+b maka
x²-x-2=0
(x-2)(x+1)

f(x) dibagi x-2 sisa 11
maka
x-2=0
x=2
f(2)=11
2a+b=11 pers(10

f(x) dibagi x+1 sisa 4
maka
x+1=0
x=-1
f(-1)=4
-a+b=4 pers(2)

eliminasikan

2a+b=11
-a+b=4
kurangkan
3a=15
a=5

2(5)+b=11
b=11-10
b=1
jadi sisanya ax+b → 5x+1

opsi jawaban D

7) f(x) : (x - 2) bersisa 11 => f(2) = 11
f(x) : (x + 1) bersisa 4 => f(-1) = 4
f(x) : (x^2 - x - 2) bersisa ax + b
f(2) = 2a + b = 11
f(-1) = -a + b = 4
------------------------ -
......... 3a = 7 => a = 7/3
-a + b = 4 => b = 4 + a = 4 + 7/3 = 19/3
Jadi sisa nya : ax + b = (7/3)x + 19/3 ..... tak ada di option

Ada kemungkinan soalnya diralat untuk sisa (x + 1) adalah -4 bukan 4

10)x^2 + 3x - 4 = (x + 4)(x - 1) => x = -4 atau x = 1
g(x) = x^4 + 2x^3 - ax^2 - 14x + b
1 . | 1 .... 2 ....... -a ......... -14 .............. b
... | ....... 2 ....... 4 ........... 4 - a .......... -10 - a
-------------------------------------------------------- +
-4 | 1 .... 4 ....... 4 - a ..... -10 - a .. | .. b - 10 - a = 0
.... | ...... -4 ...... 0 .......... 4a - 16
----------------------------------------- +
..... 1 ..... 0 ...... 4 - a .. | .. 3a - 26 => 3a = 26 => a = 26/3

b - 10 - a = 0
b = 10 + a = 10 + 26/3 = 56/3
g(x) = x^4 + 2x^3 - 26/3 x^2 - 14x + 56/3 : (x + 1) bersisa g(-1)
g(-1) = 1 - 2 - 26/3 + 14 + 56/3 = 13 + 30/3 = 13 + 10 = 23
Tak ada di option jg :(