#### Answer

Area = $\frac{a^2}{2(a-2)}$, a>2

#### Work Step by Step

Plug in the given point to solve for b,
1= -2b/a + b
a = -2b + ab
a = b(a-2)
b = a/(a-2)
Area of the triangle is A = ab/2 = $\frac{a^2}{2(a-2)}$
Area must be positive and the denominator must be non zero, hence a-2>0 giving a>2.