Question

What is the value of the expression 2x(squared) + 3xy – 4y(squared) when x = 2 and y = - 4?

Answer 1

\[2x ^{2}+3xy-4y ^{2}\]
\[2( )^{2}+3( )( )-4( )^{2}\]
\[2(2)^{2}+3(2)(-4)-4(-4)^{2}\]
\[2(4)-24-4(16)\]
\[8-24-64\]

\[-80\]