(3x + x²)² - x²(x - 5)(x + 5) + 2x(8 - 3x²)= (3x + x²)² - x²(x² - 25) + 2x(8 - 3x²) =
= 9x² + 6x³ + x⁴- x⁴ + 25x² + 16x - 6x³ = 34x² + 16x
7/(х²+6)=1/х х≠0
7х=х²+6
х²-7х+6=0
D=7²-4*6=25 (±5²)
x1=(7-5)/2=1
x2=(7+5)/2=6
-x² +6x/9 - 2x/3= -9x
-9x²+6x - 3*2x= - 9*9x
-9x²+6x-6x+81x=0
-9x²-81x=0
9x²+81x=0
x²+9x=0
x(x+9)=0
x1=0
x+9=0
x2= -9
6х+6у=5-2х-у
3х-2у=-3у-3
8х+7y=5
3х+у=-3. *(-7)
8х+7y=5
+ (-21х) -7у=21
-13х=26
х=-2
У=3
3x + 12 = - 3x + 12
3x + 3x = 12 - 12
6x = 0
x = 0
y = 3*0 + 12 = 12
Ответ
(0; 12)