`e)(2x+5)(5-2x)+(x-5)(5+4x)`
`=(25-4x^2)+(5x+4x^2-25-20x)`
`=(25-4x^2)+(-15x+4x^2-25)`
`=25-4x^2-15x+4x^2-25`
`=-15x`
`f)4x^2+4x+1-(2x-1)^2`
`=4x^2+4x+1-(4x^2-4x+1)`
`=4x^2+4x+1-4x^2+4x-1`
`=8x`
`g)(x+5)(x^2+5x+25)-10x(x+5)-x^3`
`=(x+5)(x^2+5x+25-10x)-x^3`
`=(x+5)(x^2-5x+25)-x^3`
`=x^3+125-x^3`
`=125`