Объяснение:
1) x^2-6xy+9y^2-9x^2+6xy+y^2= 10y^2-8x^2= 10* (6/2)^2-8*(-3)^2=10*36/4 -8*9=90-72=18
c^4-6c^2+9-c^4+2c^2+8+4*(25-10c+c^2)= -4c^2+17+100-40c+4c^2= 117-40c= 117+2= 119
3) m^2+10m+25-m^2+16= 10m+41= 10*(-3,5)=-35
4) a^9-4-a^9-6a-9= -13-6a= -13+12= -1
