9z²-(z+1)²
=(3z)²-(z+1)²
=(3z+z+1)(3z-z-1)
=(4z+1)(2z-1)
6(a+1)²+4(a+1)
=6(a+1)(a+1)+4(a+1)
=(6a+6)(a+1)+4(a+1)
=(6a+6+4)(a+1)
=(6a+10)(a+1)
=2(3a+5)(a+1)
9z²-(z+1)²
=(3z)²-(z+1)²
=(3z+z+1)(3z-z-1)
=(4z+1)(2z-1)
6(a+1)²+4(a+1)
=6(a+1)(a+1)+4(a+1)
=(6a+6)(a+1)+4(a+1)
=(6a+6+4)(a+1)
=(6a+10)(a+1)
=2(3a+5)(a+1)