(7x-2)(7x+2)= (2x^2-y^2)(4x^3+2xy+y^3)=
1) (7x-2)(7x+2)= 7x^2-2^2 49x^2-4 2) (2x^2-y^2)(4x^3+2xy+y^3) 2x^2+4x^3•y+2x^2•y^3-4x^3•y^2-2x•y^3-y^5= 8x^5+4x^3•y+2x^2•y^3-2x•y^3-y^5