2xpangakat dua-4x-7,tentukan x1danx2

Bab Persamaan Kuadrat
Matematika SMP Kelas VIII

2x² - 4x - 7 = 0
a = 2; b = -4; c = -7

x12 = (-b +- √(b² - 4 . a . c)) / (2 . a)
x12 = (-(-4) +- √((-4)² - 4 . 2 . (-7)) / (2 . 2)
x12 = (4 +- √(16 + 56)) / 4
x12 = (4 +- √72) / 4
x12 = (4 +- 6√2) / 4
x12 = 1 +- (3/2 √2)

x1 = 1 + (3/2 √2)
x2 = 1 - (3/2 √2)

[tex] x^{2} -4x-7=0 \\ x= \frac{-b+- \sqrt{b^2-4ac} }{2a} \\ x= 2+- \sqrt{11} \\ \\ x=2+ \sqrt{11} \\ atau \\ x=2- \sqrt{11}[/tex]