Need help ASAP !!!!!

[tex]\longrightarrow{\blue{a.\:90}}[/tex]
[tex]\large\mathfrak{{\pmb{\underline{\red{Step-by-step\:explanation}}{\red{:}}}}}[/tex]
[tex] - 3xy[/tex]
Plugging in the values "[tex]x = 5[/tex]" and "[tex] y = -6[/tex]", we have
[tex] = - 3(5)( - 6)[/tex]
[tex] = - 3( - 30)[/tex]
[tex] = 90[/tex]
[tex]\circ \: \: { \underline{ \boxed{ \sf{ \color{green}{Happy\:learning.}}}}}∘[/tex]