Question 201108
Start with the formula for tha area of a triangle:
{{{A = (1/2)bh}}} Substitute: A = 28, b = 2h+6.
{{{28 = (1/2)(2h+6)h}}} Simplify.
{{{28 = (1/2)(2h^2+6h)}}} Perfom the indicated multiplication on the right side.
{{{28 = h^2+3h}}} Subtract 28 from both sides.
{{{h^2+3h-28 = 0}}} Solve by factoring.
{{{(h+7)(h-4) = 0}}} so...
{{{h+7 = 0}}} or {{{h-4 = 0}}} then...
{{{cross(h = -7)}}} or {{{highlight(h = 4)}}} Discard the negative solution as the height, h, can only be positive.
The height is 4 meters.