<span>(8/33+13/22)/5/18=</span>0,00925925925
2x - 3y = 7
15x + 3y = 10
(+)---------------------------
17x = 17
x= 1
x=1
2*1-3y=7
x=1
2-3y=7 /-2
x=1
-3y=5 /:(-3)
x=1
y= - 5/3
x=1
y= - 1 2/3
1)
100^x - 70 * 10^(x-1) - 30 = 0
10^2x - 7 * 10^x - 30 = 0
{t = 10^x}
t^2 - 7t - 30 = 0
(t - 10)(t + 3) = 0
t = 10 -> 10^x = 10 -> x = 1
t = -3 -> 10^x = 3 -> нет вещественных решений
--> x = 1
2)
(1/2)^(2x-1) - 5^(1-2x) = 0
2^(1 - 2x) = 5^(1 - 2x)
1 - 2x = 0
x = 1/2
3)
0.2 ^ (3x-y)/(x - 2) > 1/5
{0.2 = 1/5 < 1}
(3x - y)/(x-2) <= 0
y/3 <= x < 2
или
2 < x <= y/3 (в зависимости от y)
1)х=7 3/7:4/7;
х=52/7•7/4;
х=13;
2)4х-19=5х+8;ОДЗ:4х не=18;х не=4,5;и х не=-1,6
4х-5х=8+19;
-х=27;
х=-27;
Ответ:-27;
3)х+2/3=5/6:5/7;
х+2/3=5/6•7/5;
х+2/3=1 1/6;
х=1 1/6-2/3;
х=1/2;
Ответ:0,5