Question 3170
your base definition is a good start. Your height is correct. Now for the area:


area of triangle = {{{(1/2)bh}}}


so, area = 36 = {{{(1/2)(x)(4x+2)}}}


{{{72 = 4x^2 + 2x}}}


so we get a quadratic, when we divide by 2 (to simplify a little): {{{2x^2 + x - 36 = 0}}}


Hopefully this factorises nicely. If not - use the quadratic formula.


jon.