[tex]\text{Use distributive property:}\ a(b+c)=ab+ac\\\\-2m(m+n-4)+5(-2m+2n)+n(m+4n-5)\\\\=(-2m)(m)+(-2m)(n)+(-2m)(-4)+(5)(-2m)+(5)(2n)\\+(n)(m)+(n)(4n)+(n)(-5)\\\\=-2m^2-2mn+8m-10m+10n+mn+4n^2-5n\\\\=-2m^2+4n^2+(-2mn+mn)+(8m-10m)+(10n-5n)\\\\=-2m^2+4n^2-mn-2m+5n[/tex]
