Question 936524


when {{{x = 1/2}}} and {{{y = 1/3}}}

{{{4x^2+18xy^2 -y^2}}}

{{{4(1/2)^2+18(1/2)(1/3)^2 -(1/3)^2}}} 


{{{4(1/4)+18(1/2)(1/9) -(1/9)}}} 


{{{cross(4)(1/cross(4))+cross(18)cross(9)1(1/cross(2))(1/cross(9)1) -(1/9)}}} 


{{{1+1 -(1/9)}}}


{{{2 -(1/9)}}}


{{{18/9 -(1/9)}}}


{{{17/9}}}


{{{1(8/9)}}}