Question 673529
Area of a triangle {{{A= (1/2 ) b * h}}}

shortest side {{{x-4y}}} ft. and the middle length side {{{x+6y}}} ft; note that one of them could be base {{{b}}} and another one could be {{{h}}}...whatever you choose works 

{{{A= (1/2 ) (x-4y)ft * (x+6y)ft}}}

{{{A= (1/2 ) (x^2+6xy-4xy-24y^2)ft^2 }}}

{{{A= (1/2 ) (x^2+2xy-24y^2)ft^2 }}}

{{{A=  ((1/2)x^2+xy-12y^2)ft^2 }}}