The right answer is A ! :)
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:
B) In y = 25x, the value of y is 25 times the value of x, and in y = x + 25, the value of y is 25 more than the value of x.
Out of all the answer choices, b makes the most sense.
25x can be translated as 25 times x.
x + 25 can be translated as 25 more than a number.
Hope this helps!
Your answer for Q is rotated over the period and flipped upside down.