Question

Упростите выражение: (m+3)(m-3)-m(m+1)

Answer 1

 (m+3)(m-3)-m(m+1)=m²-9-m²-m=-9-m

Answer 2

$(m+3)(m-3)-m(m+1)=m^{2}-9-m^{2}-m=(m^{2}-m^{2})-m-9=-m-9=-(m+9)$