20х0,7+4х0,7(4х1,4-5х1,4):1,4=
1)4х1,4=5,6
2)5х1,4=7
3)5,6-7=-1,4
4)20х0,7=14
5)4х0,7=2,8
6)14+2,8=16,8
7)16,8х(-1,4)=-23,52
Данное уравнение равносильно двум следующим:
x² + 3x = 2x - 6 или x² + 3x = - 2x + 6
x² + x + 6 = 0 x² + 5x - 6 = 0
D = b²-4ac = 1 - 24= D = 25 - 4×(-6) = 25+24 = 49
= - 23 - отрицательный, x = 1 или x = - 6
корней нет
![f(2+x)= \frac{((2+x)^2+6(2+x)+8)^3}{6(2+x)+ \sqrt{24}+ \sqrt{42} } = \frac{(x^2+4x+4+12+6x+8)^3}{6x+12+ \sqrt{24} + \sqrt{42} } \ \textless \ 0](https://tex.z-dn.net/?f=f%282%2Bx%29%3D+%5Cfrac%7B%28%282%2Bx%29%5E2%2B6%282%2Bx%29%2B8%29%5E3%7D%7B6%282%2Bx%29%2B+%5Csqrt%7B24%7D%2B+%5Csqrt%7B42%7D+%7D+%3D+%5Cfrac%7B%28x%5E2%2B4x%2B4%2B12%2B6x%2B8%29%5E3%7D%7B6x%2B12%2B+%5Csqrt%7B24%7D+%2B+%5Csqrt%7B42%7D+%7D+%5C+%5Ctextless+%5C+0)
![\frac{(x^2+10x+24)^3}{6x+12+ \sqrt{24} + \sqrt{42} } \ \textless \ 0](https://tex.z-dn.net/?f=%5Cfrac%7B%28x%5E2%2B10x%2B24%29%5E3%7D%7B6x%2B12%2B+%5Csqrt%7B24%7D+%2B+%5Csqrt%7B42%7D+%7D+%5C+%5Ctextless+%5C+0)
![\frac{((x+4)(x+6))^3}{6x+12+ \sqrt{24} + \sqrt{42} } \ \textless \ 0](https://tex.z-dn.net/?f=+%5Cfrac%7B%28%28x%2B4%29%28x%2B6%29%29%5E3%7D%7B6x%2B12%2B+%5Csqrt%7B24%7D+%2B+%5Csqrt%7B42%7D+%7D+%5C+%5Ctextless+%5C+0)
Особые точки этого неравенства:
x1 = -6; x2 = -4; x3 = (-12-√24-√42)/6 ≈ -3,8966
По методу интервалов
x ∈ (-oo; -6) U (-4; (-12-√24-√42)/6)