ПЛИИИЗ!!!!СРОЧНО!!!!!!!!!!!
1) x не= 2 и -1 2) а) 2b^4/a^2 б) x(x+3y)/y(x+3y)=x/y 3) (c^2/c^2+2c)-(c^2-2c-4/c^2+2c)=2c+4/c^2+2c 4) (a^2-2b/a)-(a^2/a)=-2b/a=-2*4/0.2=-8/0.2=-40