2(1-3x)²-2(3x+1)(1-3x) = 2(1-3x)*(1-3x-(3x+1)) = 2(1-3x)*(1-3x-3x-1) = 2(1-3x)*(-6x) = -12x*(1-3x) = -12x+36x = 3,6x-1,2x = 2,4x
Не забудь поставить спасибо
2log(3) x - 3 log(3) y = -11
3log(3) x + 2log(3) y = 3
ОДЗ x>0 y>0
умножаем первое на 2, второе на 3 и складываем
4log(3) x - 6 log(3) y = -22
9log(3) x + 6log(3) y = 9
4log(3) x - 6 log(3) y + 9log(3) x + 6log(3) y = -22 + 9
13log(3) x = -13
log(3) x = -1
x = 1/3
2*(-1) - 3log(3) y = -11
-3log(3) y = -9
log(3) y = 3
y = 27
Ответ {1/3, 27}
-y = 56 - 7x
y = 7x - 56
7х = 56+у
х = (56+у)/7
Y=x²+400/x
y`=2-400/x²=(2x²-400)/x²=0
2x²-400=0
x²=200
x=-10√2∈[-28;-2]
x=10√2∉[-28;-2]
y(-28)=784-400/28=784-14 2/7=769 5/7 наиб
y(-10√2)=200-400/10√2=200-20√2≈172
y(-2)=4-400/2=4-200=-196