42:1 1/3 - 15,6 + 1 2/3 = 17 17/30
1) 42:1 1/3 = 42:4/3 = 42·3:4 = 31,5
2) 31,5 - 15,6 = 15,9
3) 15,9 + 1 2/3 = 159/10 + 5/3 = (159·3 + 5·10)/30 = 527/30 = 17 17/30
Х^2+2х-3=0
х^2-7х-5=0
2х^2+22х-17=0
х^2-4-3х=0 или х^2-3х-4=0
3(х^2-1)+х=0 ; 3х^2+х-3=0
х^2-2х+3х-6=0 ; х^2+х-6=0
(√9-4√5+2)²=9-4√5+4=9-√80+4=13-√80
2^x+4/2^x=5
2^x=t
t+4/t-5=0
t^2-5t+4=0
t1=1 t2=4
2^x=1 x=0
2^x=4 x=2
2) 1=log3(3)
(x+7)/(x-5)>3
(x+7)/(x-5)-3>0
(x+7-3x+15)/(x-5)>0
(11-x)/(x-5)>0
----<0-----5---->0------11-----<0------
ОДЗ (x+7)/(x-5)>0
__>0_____-7______<0_______5_____>0_____
x (5;11)