A) D = 25 - 4(-6) = 25 + 24 = 49
x1 = (-5+7)/2 = 1
x2 = (-5-7)/2 = -6
б) D = 9 - 8 = 1
x1 = (-3+1)/2 = -1
x2 = (-3-1)/2 = -2
в) D = 4 + 12 = 16
z1 = (2+4)/2 = 3
z2 = (2-4)/2 = -1
г) D = 1 + 24 = 25
t1 = (-1+5)/2 = 2
t2 = (-1-5)/2 = -3
д) D = 16 + 84 = 100
x1 = (4+10)/2 = 7
x2 = (4-10)/2 = -3
е) D = 81 - 72 = 9
x1 = (-9+3)/2 = -3
x2 = (-9-3)/2 = -6
ж) D = 49 - 24 = 25
a1 = (7+5)/2 = 6
a2 = (7-5)/2 = 1
з) D = 16 + 240 = 256
b1 = (4+16)/2 = 10
b2 = (4-16)/2 = -6
-log5 4x+log5 (x²+75)=1
log5 (x²+75)/4x=log5 5
x²+75)/4x=5 x²-20x+75=0 привели к общемузнаменателю 4х≠0
D=20²-4*1*75=400-300=100 x1=20+√100)/2=30/2=15 x2=20-10)/2=5
ответ 5 15
19/25=0,76≈0,8 )))))))))))))))))))))))))))