Tolong jawab dong. No 5 atau 6 . Klo dua duanya bisa syukur. Makasih

5) g(x) = x^3 + ax^2 + x + 10 akar-akarnya merupakan akar dari f(x)
Misal akar lain dari f(x) adalah (x + p)
f(x) = x^4 + x^3 + bx^2 + 100x + c

f(x) = g(x) . (x + p)
f(x) = (x^3 + ax^2 + x + 10)(x + p)
f(x) = x^4 + px^3 + ax^3 + apx^2 + x^2 + px + 10x + 10p
f(x) = x^4 + (p + a)x^3 + (ap + 1)x^2 + (p + 10)x + 10p
1) x => p + 10 = 100 => p = 90
2) konstanta => c = 10p => c = 10(90) => c = 900
3) x^3 => p + a = 1 => a = 1 - p => a = 1 - 90 => a = -89
4) x^2 => b = ap + 1 => b = (-89)(90) + 1 => b = -8009
Jadi
f(x) = x^4 + x^3 + bx^2 + 100x + c
f(1) = 1^4 + 1^3 + (-8009)(1)^2 + 100(1) + 900
f(1) = 1 + 1 - 8009 + 100 + 900
f(1) = -7007

6) A(3,1,0), B(a^2, -2, -a), C(a + 3, a^2 - 1, 6), -1 ≤ a < 3
Nilai maksimum AB.AC = ....
AB = b - a = (a^2 - 3, -3, -a)
AC = c - a = (a, a^2 - 2, 6)
AB.AC = (a^2 - 3)(a) + (-3)(a^2 - 2) + (-a)(6)
= a^3 - 3a - 3a^2 + 6 - 6a
= a^3 - 3a^2 - 9a + 6
Turunan => 3a^2 - 6a - 9 = 0
=> a^2 - 2a - 3 = 0
=> (a - 3)(a + 1) = 0
=> a = 3 atau a = -1
++++ (-1) ---- (3) ++++
karena maksimum (++ --) maka a = -1
AB . AC = a^3 - 3a^2 - 9a + 6
= (-1)^3 - 3(-1)^2 - 9(-1) + 6
= -1 - 3 + 9 + 6
= 11