7x²-7y²+5x+5y
=7(x²-y²)+5(x+y)
=7(x+y)(x-y)+5(x+y)
=(x+y)[7(x-y)+5]
=(x+y)(7x-7y+5)
a²b+a²-b³-b²
=(a²b-b³)+(a²-b²)
=b(a²-b²)+(a²-b²)
=(a²-b²)(b+1)
=(a+b)(a-b)(b+1)