Matematika.. Mohon bantuannya Gambar 1 nomer 8 A smpai D

Matematika.. Mohon bantuannya
Gambar 1 nomer 8
A smpai D

Matematika.. Mohon bantuannya
Gambar 1 nomer 8
A smpai D

Cukup ingat rumus abc , yaitu :
$boxed{displaystyle x_1,x_2~~=~~frac{-b~pm~sqrt{b^2-4ac}}{2a}}$

bagian a
x² + kx – 3 = 0
maka : a = 1 , b = k dan c = – 3
penyelesaian :
$displaystyle x_1,x_2~~=~~frac{-(k)~pm~sqrt{(k)^2-4(1)(-3)}}{2(1)} \ \ x_1,x_2~~=~~frac{-k~pm~sqrt{k^2+12}}{2} \ \ \ .$

bagian b
x² + 2x – k = 0
maka : a = 1 , b = 2 dan c = – k
penyelesaian :
$displaystyle x_1,x_2~~=~~frac{-2~pm~sqrt{(2)^2-4(1)(-k)}}{2(1)} \ \ x_1,x_2~~=~~frac{-2~pm~sqrt{4+4k}}{2} \ \ x_1,x_2~~=~~frac{-2~pm~sqrt{4(1+k)}}{2} \ x_1,x_2~~=~~frac{-2~pm~2sqrt{1+k}}{2}\ x_1,x_2~~=~~-1~pm~sqrt{k+1} \ .\.$

bagian c
x² + (k – 1)x – k = 0
maka : a = 1 , b = (k – 1) dan c = – k
penyelesaian :
$displaystyle x_1,x_2~~=~~frac{-(k-1)~pm~sqrt{(k-1)^2~-~4(1)(-k)}}{2(1)} \ \ x_1,x_2~~=~~frac{1-k~pm~sqrt{(k^2-2k+1)~+~4k}}{2} \ x_1,x_2~~=~~frac{1-k~pm~sqrt{k^2+2k+1}}{2} \ x_1,x_2~~=~~frac{1-k~pm~(k+1)}{2} \ x_1~=~1 \ x_2~=~-k\ .\.$

bagian d
x² + (2 – k)x – 2k = 0
maka : a = 1 , b = (2 – k) dan c = -2k
penyelesaian :
$displaystyle x_1,x_2~~=~~frac{-(2-k)~pm~sqrt{(2-k)^2-4(1)(-2k)}}{2(1)} \ \ x_1,x_2~~=~~frac{k-2~pm~sqrt{4-4k+k^2+8k}}{2} \ \ x_1,x_2~~=~~frac{k-2~pm~sqrt{k^2+4k+4}}{2}\ \ x_1,x_2~~=~~frac{k-2~pm~(k+2)}{2}\ \ x_1~=~k\ x_2~=~-2\ .$