1) x^2-25-(x^2+3x) по формуле (a-b)(a+b)=a^2-b^2
x^2-25-x^2-3x
-25-3x
3)x^2-6x+2x-12-(x^2-49)<30-3x<br> x^2-6x+2x-12-x^2+49<30-3x<br> -4x+37<30-3x<br> -x<-7<br>x>7
4) 9x^2+12x+4-(16-24x+9x^2)<14+37x<br>36x-12<14+37x<br>36x-37x<14+12 x>-26
x>-26
2) (4+y)*(4-y)+y^2+5y>6y-20
16-y^2+Y^2+5y>6y-20
5y-6y>-20-16
-y>-36
y<36