Answer:
Substitute in the values of both given coordinates & form 2 equations:
Find the value of B from the equation 2A - B = 1:
Substitute in the B-value to the other equation:
Find the B-value using the equation from before:
Therefore the equation Ax + By = 1 would equal:
You can focus on the two sub-triangles ABC and ACD
We know that they are both right triangles, because we're given that AC and BD are perpendicular.
The sides AB and AD are the hypothenuses of these triangles, so we know their length through the pythagorean theorem:
But since we're given , the expressions for AD and AB are actually the same expression. This proves that AD=AB, and thus that the triangle is isosceles.
