Question

Diketahui x1 dan x2 adalah akar-akar persamaan kuadrat x² − 3x − 4 = 0. Jika x1 > x2 , maka nilai dari 2x1 − 3x2 adalah​

Answer 1

Persamaan Kuadrat

[Metode Menfaktorkan]

..

Akar - Akar

[tex]\begin{aligned} x² - 3x - 4 &= 0 \\ x² + x - 4x - 4 &= 0 \\ x(x + 1) - 4(x + 1) &= 0 \\ (x + 1)(x - 4) &= 0 \end{aligned}[/tex]

[tex]\begin{aligned}~~~~ x + 1 = 0 &\vee x - 4 = 0 \\ x_2 = -1 &\vee x_1 = 4 \end{aligned}[/tex]

• Disebutkan dalam soal bahwasanya x₁ > x₂

..

Nilai dari 2x₁ - 3x₂

[tex]\begin{aligned} 2x_1 - 3x_2 &= 2(4) - 3(-1) \\&= 8 - (-3) \\&= 8 + 3 \\&= \boxed{11} \end{aligned}[/tex]

[tex]\begin{array}{lr}\texttt{Selamat Menunaikan Ibadah Puasa}\end{array}[/tex]

[tex]\boxed{\colorbox{ccddff}{Answered by Danial Alf'at | 04 - 04 - 2023}}[/tex]

Answer 2

x² - 3x - 4 = 0

a = 1

b = -3

c = -4

abc :

= -B ± √B² - 4AC/2A

= 3 ± √(-3)² - 4(1(-4)/2(1)

= 3 ± √9 + 16/2

= 3 ± √25/2

= 3 ± 5/2

X1 = 3 + 5/2 = 8/2 = 4

X2 = 3 - 5/2 = -2/2 = -1

MAKA 2X1 - 3X2 :

= (2 × 4) - (3 × (-1)

= 8 - (-3)

= 8 + 3

= 11

[tex]\boxed { \color{lime} \mathcal{INFINITE \: WORLD}}[/tex]