QUIZ - [16.875]1. 2³ -2 = 2. (2 + x)³ = 8, x = ?3. x² -2x + 4 = 0, x = ?

QUIZ – [16.875]1. 2³ -2 = 2. (2 + x)³ = 8, x = ?3. x² -2x + 4 = 0, x = ?

Penjelasan dengan langkah-langkah:

Nomor 1

2³ – 2

= 8 – 2

= 6

Nomor 2

(2 + x)³ = 8

2 + x = 2

x = 0

Nomor 3

x² – 2x + 4 = 0

$begin{align}x & = frac{ - ( - 2) pm sqrt{ {( - 2)}^{2} - 4(1)(4)} }{2(1)} \ x & = frac{2 pm sqrt{4 - 16} }{2} \ x & = 1 pm sqrt{1 - 4} \ x& = 1 pm sqrt{-3} end{align}$

Jawab:

Penjelasan dengan langkah-langkah:

1) 2³-2 = 8-2 = 6

2) (x+2)³ = 8

(x+2)³-2³ = 0

(x+2 – 2)((x+2)²+2² + (x+2)*2) = 0

x((x+2)²+2(x+2)+1 + 3) = 0

x((x+2+1)² + 3) = 0

x((x+3)² – (√(-3))²) = 0

x((x+3)² – (√3 i)²) = 0

x(x+3 – √3 i)(x + 3 + √3 i) = 0

x = 0 atau -3+√3 i atau -3 – √3 i

$boxed{textbf{Large{$boldsymbol{x = 0text{ atau } -sqrt{12} ; e^{textstyle -i;dfrac{pi }{6}}text{ atau } -sqrt{12} ; e^{textstyle i;dfrac{pi }{6}}}$}}}$

3) x²-2x+4 = 0

x²-2x+1 + 3 = 0

(x-1)² = -3

x = 1 ±√3 i

$boxed{textbf{Large{$boldsymbol{x = 2 ; e^{textstyle i;dfrac{pi }{3}}text{ atau } 2; e^{textstyle- i;dfrac{pi }{3}}}$}}}$