Answer:
On the graphing calculator, use the function normCdf, where
- lower bound = -9999
- upper bound = 210
- mean = 250
- standard deviation = 46
It will result in normCdf(-9999,210,250,46) ≈ 0.192269 or 19.2269%
We first obtain the equation of the lines bounding R.
For the line with points (0, 0) and (8, 1), the equation is given by:

For the line with points (0, 0) and (1, 8), the equation is given by:

For the line with points (8, 1) and (1, 8), the equation is given by:

The Jacobian determinant is given by

The integrand x - 3y is transformed as 8u + v - 3(u + 8v) = 8u + v - 3u - 24v = 5u - 23v
Therefore, the integration is given by: