1) * (*-5) = 24; 2) * (*+7) = 78; 3) * (*+8) = 105.

1) Х (Х-5) = 24

Х^2-5X-24=0

X1*X2=-24

X1+X2=5

X1=-3

X2=8

2) x (x+7) = 78

x^2+7x-78=0

x1*x2=-78

x1+x2=-7

x1=-13

x2=5

3) x (x+8) = 105

x^2+8x-105=0

x1*x2=-105

x1+x2=-8

x1=7

x2=-15

1.

x^2-5x-24=0

D=25-4*1 * (-24) = 25+96=121 (корень=11)

x1 = (5+11) / 2=8

x2 = (5-11) / 2=-3

2.

x^2+7x-78=0

D=49-4*1 * (-78) = 49+312=361 (корень=19)

x1 = (-7+19) / 2=6

x2 = (-7-19) / 2=-13

3.

x^2+8x-105=0

D=64-4*1 * (-105) = 64+420=484 (корень=22)

x1 = (-8+22) / 2=7

x2 = (-8-22) / 2=-15