18,6-12,4х=20-12,4х-1,4
-12,4х+12,4х=-1,4-18,6
х=-17,2
1) x² + 12x + 27 = 0
D = 12² - 4*27 = 144 - 108 = 36
X1,2 = (- 12 + - √36)/2 = (- 12 + - 6)/2
X1 = (- 12 + 6)/2 = - 3
X2 = (- 12 - 6)/2 = - 9
Ответ : - 3; - 9
2) 8x² - 13x - 6 = 0
D = 13² - 4*(-6)*8 = 169 + 192 =361
X1,2 = (13 + - √361)/16 = (13 + - 19)/16
X1 = (13 + 19)/16 = 32/16 = 2
X2 = (13 - 19)/16 = - 6/16 = - 0, 375
Ответ: - 0,375; 2
<span>Х</span>² <span>- (11х+2)/6 = 0
6x</span>² - 11x - 2 = 0
<span>D = 121 + 4*6*2 = 169
x</span>₁ = (11 - 13)/12
<span>x</span>₁ = - 1/6
<span>x</span>₂ = (11 + 13)/12
<span>x</span>₂ = 24/12
<span>x</span>₂ = 2<span>
</span>