Question 106170
{{{A = 75}}} sq ft
{{{A = (1/2)*b*h}}}
Let the base = d
Let the height = h
{{{h = 2d - 5}}}
{{{A = (1/2)*d*(2d-5)}}}
{{{75 = (1/2)*d*(2d-5)}}}
{{{150 = 2d^2 - 5d}}}
{{{2d^2 - 5d - 150 = 0}}}
Use  {{{d = (-b +- sqrt( b^2-4*a*c ))/(2*a) }}}
when equation is {{{ax^2 + bx + c = 0}}}
a = 2
b = -5
c = -150
{{{d = (5 +- sqrt( (-5)^2-4*2*(-150) ))/(2*2) }}}
{{{d = (5 +- sqrt(25 + 1200)) / 4}}}
{{{d = (5 +- sqrt(1225)) / 4}}}
{{{d = (5 + 35) / 4}}} (the negative sign makes no sense in this problem)
{{{d = 10}}} ft  This is the base
{{{h = 2d - 5}}}
{{{h = 20 - 5}}}
{{{h = 15}}} ft This is the height