Ответ: 9 та 21.
Объяснение:
10.
Нехай х та у - натуральні числа. ⇒
{y-2x=3 {y=2x+3
{x*y=189 {x*(2x+3)=189
{2x²+3x-189=0 D=1521 √D=39 x₁=-10,5 ∉ x₂=9 ∈. ⇒
y=2*9+3=18+3
y=21.
8.
(x²+1)²-10*(x²+1)+25=0
Нехай x²+1=t ⇒
t²-10t+25=0
t²-2*t*5+5²=0
(t-5)²=0
t-5=0
x²+1-5=0
x²-4=0
x²-2²=0
(x+2)(x-2)=0
x₁=-2 x₂=2.
9.
ОДЗ: х≠0
Нехай
⇒
t²+2t-35=0 D=144 √D=12
![t_{1} =\frac{x^{2} -6}{x} =5;\\x^{2} -6=5x;\\x^{2}-5x-6=0 \\D=49;\sqrt{D}=7\\ x_{1} =6 ; x_{2} =-1\\t_{2}=\frac{x^{2} -6}{x} =-7 \\x^{2}- 6=-7x\\x^{2} +7x-6=0\\D=73; \sqrt{D}=\sqrt{73}\\x_{3}=\frac{-7-\sqrt{73} }{2} ;x_{4} =\frac{-7+\sqrt{73} }{2} . t_{1} =\frac{x^{2} -6}{x} =5;\\x^{2} -6=5x;\\x^{2}-5x-6=0 \\D=49;\sqrt{D}=7\\ x_{1} =6 ; x_{2} =-1\\t_{2}=\frac{x^{2} -6}{x} =-7 \\x^{2}- 6=-7x\\x^{2} +7x-6=0\\D=73; \sqrt{D}=\sqrt{73}\\x_{3}=\frac{-7-\sqrt{73} }{2} ;x_{4} =\frac{-7+\sqrt{73} }{2} .](https://tex.z-dn.net/?f=t_%7B1%7D%20%3D%5Cfrac%7Bx%5E%7B2%7D%20-6%7D%7Bx%7D%20%3D5%3B%5C%5Cx%5E%7B2%7D%20-6%3D5x%3B%5C%5Cx%5E%7B2%7D-5x-6%3D0%20%5C%5CD%3D49%3B%5Csqrt%7BD%7D%3D7%5C%5C%20x_%7B1%7D%20%3D6%20%20%3B%20x_%7B2%7D%20%3D-1%5C%5Ct_%7B2%7D%3D%5Cfrac%7Bx%5E%7B2%7D%20-6%7D%7Bx%7D%20%3D-7%20%5C%5Cx%5E%7B2%7D-%206%3D-7x%5C%5Cx%5E%7B2%7D%20%2B7x-6%3D0%5C%5CD%3D73%3B%20%5Csqrt%7BD%7D%3D%5Csqrt%7B73%7D%5C%5Cx_%7B3%7D%3D%5Cfrac%7B-7-%5Csqrt%7B73%7D%20%7D%7B2%7D%20%20%3Bx_%7B4%7D%20%3D%5Cfrac%7B-7%2B%5Csqrt%7B73%7D%20%7D%7B2%7D%20.)