Answer:
Step-by-step explanation:
1.
[tex](-4)(-9)\\\mathrm{Remove\:parentheses}:\quad \left(-a\right)=-a,\:-\left(-a\right)=a\\=4\times\:9\\= 36[/tex]
2.
[tex](-4)(9)\\\\\mathrm{Remove\:parentheses}:\quad \left(a\right)=a\\=-4\times\:9\\\\\mathrm{Multiply\:the\:numbers:}\:4\times\:9=36\\=-36[/tex]
3.
[tex](6)(6)\\\\\mathrm{Remove\:parentheses}:\quad \left(a\right)=a\\=6\times\:6\\\\\mathrm{Multiply\:the\:numbers:}\:6\times\:6\\=36[/tex]
4.
[tex](-6)(-6)\\\\\mathrm{Remove\:parentheses}:\quad \left(-a\right)=-a,\:-\left(-a\right)=a\\=6\times 6\\\\\mathrm{Multiply\:the\:numbers:}\:6\times\:6\\=36[/tex]
5.
[tex](6)(-6)\\\\\mathrm{Remove\:parentheses}:\quad \left(a\right)=a\\=-6\times 6\\\\\mathrm{Multiply\:the\:numbers:}\:6\times \:6=36\\=-36[/tex]