Answer
$ \frac{10}{7x^4}\times m^2$
Work Step by Step
The area of the triangle is
$\frac{1}{2} \times \frac{4}{x} m \times \frac{5x^{-3}}{7}m$
$=\frac{1}{2} \times \frac{20x^{-3}}{7x} m^2 = \frac{10x^{-3}}{7x^1} m^2 = \frac{10x^{-3-1}}{7} m^2 = \frac{10}{7}\times x^{-4} \times m^2 = \frac{10}{7}\times \frac{1}{x^4} \times m^2 = \frac{10}{7x^4}\times m^2$
