Если ты про это 2-5х>0, то решать вот так
-5х>-2
х<0, 4
49-х^2+х^2+6х+9=40-6х
Если х=-3,5,то 40-6•(-3,5)=40-21=19
![1)\frac{1}{9} x\geq-1\\\frac{1}{9}x*9 \geq-1*9\\x\geq -9](https://tex.z-dn.net/?f=1%29%5Cfrac%7B1%7D%7B9%7D+x%5Cgeq-1%5C%5C%5Cfrac%7B1%7D%7B9%7Dx%2A9+%5Cgeq-1%2A9%5C%5Cx%5Cgeq+-9)
x ∈ [- 9 ; + ∞)
2)3 - 8x < 0
- 8x < - 3
x > 0,375
x ∈ (0,375 ; + ∞)
3) 1,4 - 4(2x + 1) > 1,8 - 3x
1,4 - 8x - 4 > 1,8 - 3x
- 8x + 3x > 1,8 - 1,4 + 4
- 5x > 4,4
x < - 0,88
x ∈ (- ∞ ; - 0,88)
![4)\frac{4-a}{3}> \frac{5-3a}{5}\\\frac{4-a}{3}*15> \frac{5-3a}{5}*15\\5(4-a)>3(5-3a)\\20-5a>15-9a\\-5a+9a>15-20\\4a>-5\\a>-1,25](https://tex.z-dn.net/?f=4%29%5Cfrac%7B4-a%7D%7B3%7D%3E+%5Cfrac%7B5-3a%7D%7B5%7D%5C%5C%5Cfrac%7B4-a%7D%7B3%7D%2A15%3E+%5Cfrac%7B5-3a%7D%7B5%7D%2A15%5C%5C5%284-a%29%3E3%285-3a%29%5C%5C20-5a%3E15-9a%5C%5C-5a%2B9a%3E15-20%5C%5C4a%3E-5%5C%5Ca%3E-1%2C25)
a ∈ (- 1,25 ; + ∞)