X³+3x²-4=0
(x-1)(x²+4x+4)=0
(x-1)(x+2)²=0
x=1
x=2
Ответ x=1
S- расстояние AB
25 минут=5/12 часа
36 минут=3/5 часа
S:5*12=v1
S:3*5=v2
(S:5*12+S:3*5)*t=S
(12:5+5:3)*t=1
(36+25)*t=15
61t=15
<span>t=15/61 часа</span>
4n = 30 - 13m
n = 7,5 - 3,25m
- 13m - 3n = - 29
- 13m - 3( 7,5 - 3,25m ) = - 29
- 13m - 22,5 + 9,75m = - 29
- 3,25m = - 6,5
m = 2
n = 7,5 - 3,25•2 = 7,5 - 6,5 = 1
![\sqrt{x+6-4 \sqrt{x+2} } + \sqrt{11+x-6 \sqrt{x+2} }=1](https://tex.z-dn.net/?f=%20%5Csqrt%7Bx%2B6-4%20%5Csqrt%7Bx%2B2%7D%20%7D%20%2B%20%5Csqrt%7B11%2Bx-6%20%5Csqrt%7Bx%2B2%7D%20%7D%3D1)
![\sqrt{x+6-4 \sqrt{x+2} }=\sqrt{(\sqrt{x+2}-2)^2}=\sqrt{x+2}-2](https://tex.z-dn.net/?f=%5Csqrt%7Bx%2B6-4%20%5Csqrt%7Bx%2B2%7D%20%7D%3D%5Csqrt%7B%28%5Csqrt%7Bx%2B2%7D-2%29%5E2%7D%3D%5Csqrt%7Bx%2B2%7D-2)
![\sqrt{11+x-6 \sqrt{x+2} }=\sqrt{(3-\sqrt{x+2})^2}=3-\sqrt{x+2}](https://tex.z-dn.net/?f=%5Csqrt%7B11%2Bx-6%20%5Csqrt%7Bx%2B2%7D%20%7D%3D%5Csqrt%7B%283-%5Csqrt%7Bx%2B2%7D%29%5E2%7D%3D3-%5Csqrt%7Bx%2B2%7D)
отсюда
![\sqrt{x+2}-2+3-\sqrt{x+2}=1 \\ 3-2=1](https://tex.z-dn.net/?f=%5Csqrt%7Bx%2B2%7D-2%2B3-%5Csqrt%7Bx%2B2%7D%3D1%20%5C%5C%203-2%3D1)
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![\sqrt{x+2}](https://tex.z-dn.net/?f=%5Csqrt%7Bx%2B2%7D)
-любое число, но х+2≥0 ⇒ х ≥ -2