After plugging in X =1 and Y=-3 your answer would be -14
First you have to find the angle B (check attachment)

Then you can find the last angle inside the triangle, which I'll call C

Now you can find angle A

5(x − 4)^2
5(x - 4)(x - 4)
5(x^2 - 8x + 16)
5x^2 - 40x + 80
Did you follow?
If you would like to know what is 18/8 as a mixed number, you can calculate this using the following steps:
18/8 = 18/2 / 8/2 = 9/4 = 2 1/4
The correct result would be 2 1/4.