A)2*x-3*x*y+7-(3*x-5*x*y)=-x-3*x*y+7+5*x*y=-x+2*x*y+7
b) 3*a^3*(2*a^2-4)=(6*a^2-12)*a^3=6*a^5-12*a^3
c) (2*y+c)*(3*y-c)=6*y^2+y*c-c^2
5^(-1)≤5^х+4≤5^3
х= -1; 0; 1; 2.
1) (10x + 9) * x = 8 - (1 - 5x)(2x + 3)
10x² + 9x = 8 - (2x + 3 - 10x² - 15x)
10x² + 9x = 8 + 13x- 3 + 10x²
10x² + 9x - 13x - 10x² = 5
- 4x = 5
x = - 1,25
![2) \frac{2x+3}{6}-\frac{1-4x}{8} =1\\\\\frac{2x+3}{6}*24-\frac{1-4x}{8}*24=1*24\\\\4(2x+3)-3(1-4x)=24\\\\8x+12-3+12x=24\\\\20x+9=24\\\\20x=15\\\\x=0,75](https://tex.z-dn.net/?f=2%29%20%5Cfrac%7B2x%2B3%7D%7B6%7D-%5Cfrac%7B1-4x%7D%7B8%7D%20%3D1%5C%5C%5C%5C%5Cfrac%7B2x%2B3%7D%7B6%7D%2A24-%5Cfrac%7B1-4x%7D%7B8%7D%2A24%3D1%2A24%5C%5C%5C%5C4%282x%2B3%29-3%281-4x%29%3D24%5C%5C%5C%5C8x%2B12-3%2B12x%3D24%5C%5C%5C%5C20x%2B9%3D24%5C%5C%5C%5C20x%3D15%5C%5C%5C%5Cx%3D0%2C75)