Ответ:
Объяснение:
а) х²-5х+4=0
D = b²-4ac = 25-4*1*4=25-16=9
x1= = = 1
x2 = = = 4
б) y²+9y=0
D = b²-4ac = 81-4*1*0=81
y1= = = -9
y2 = = = 0
2 вариант решения:
y²+9y=0
y(y+9)=0
y1=0 y+9=0
y2=-9
в) 2t²-72=0
D = b²-4ac = 0²-4*2*(-72) = 576
t1= = = -6
t2 = = = 6
2t²-72=0
t² = 72 : 2
t² = 36
t = ±√36
t1 = 6
t2 = -6
г) 7z²-z-8=0
D = b²-4ac = (-1)² -4*7* (-8) = 1+224=225
t1= =
t2 = = ≈ 1.14
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Ответ:
Объяснение:
а) х²-5х+4=0
D = b²-4ac = 25-4*1*4=25-16=9
x1= = = 1
x2 = = = 4
б) y²+9y=0
D = b²-4ac = 81-4*1*0=81
y1= = = -9
y2 = = = 0
2 вариант решения:
y²+9y=0
y(y+9)=0
y1=0 y+9=0
y2=-9
в) 2t²-72=0
D = b²-4ac = 0²-4*2*(-72) = 576
t1= = = -6
t2 = = = 6
2 вариант решения:
2t²-72=0
t² = 72 : 2
t² = 36
t = ±√36
t1 = 6
t2 = -6
г) 7z²-z-8=0
D = b²-4ac = (-1)² -4*7* (-8) = 1+224=225
t1= =
t2 = = ≈ 1.14