Введение в математический анализ / 2 вариант

1)   0,3x+8=2       0.3x=2-8     0.3x=-6    x=-6/0.3      x =  -202)   4-x=1+4x        -x-4x=1-4      -5x=-3    x=-3/(-5)     x  =  0.63)    7-2(x+3)=9-6x      -2x+6x=9-7+6     4x=8    x=8/4     x  =  24)     4(x-0.5)-2(x+0.3)=-2.6       4x-2x = -2.6+2+0.6     2x = 0    x=0/2     x  =  05)      0.4x-6= -12         0.4x = -12+6      0.4x = -6     x  =  -6/0.4        x   =   -156)       x+6=5+4x    x-4x=5-6        -3x = -1     x  =  -1/(-3)         x  =  1/37)       13-3(x+1) = 4-5x      -3x +5x = 4-13+3         2x = -6     x  =  -6/2     x  =  -38)        0.2(3x-5)-0.3(x-1) = -0.7     0.6x - 0.3x = -0.7+1-0.3   0.3x = 0    x = 0/0.3      x  =  0 1)        (7y-2)/(5y-4)>2           (7y-2 -2(5y-4)) / (5y-4) > 0           1) случай    {7y-2-10y+8 > 0      {-3y>-6   {y<-6/(-3)       {y < 2             0.8 < x < 2                                 {5y-4  > 0                 {5y > 4   {y>4/5             {y > 0.8            2)случай     {7y-2-10y + 8<0       {-3y<-6    {y>-6/(-3)    {y > 2      Пустое  множество                                  {5y-4 < 0                  {5y < 4      {y<4/5         {y < 0.8ответ.         ( 0,8;      2) 2)          8y+2 -(5y+3) > 5              8y - 5y > 5-2+3              3y > 6              y > 6/3              y > 23)          3*(2y+1.5)-(3+2y+1.5) > 8              6y-2y > 8-4.5+4.5              4y > 8              y> 8/4              y  >  24)          4*(3y-0.5) - 4 -3y-0.5 >3.5              12y - 3y  <  3.5 +2+4+0.5               9y  <  10                y <  10/9