<span>Complementary angles sum up to 90 degrees and supplementary angles sum up to 180 (I remember that because they are alphabetical).
90 - 71.4 = 18.6
180 - 71.4 = 108.6
Therefore, D. is the answer.</span>
The answers are x=4 and y=323/2
1) 40/2x-3=8
Multiply both sides by 2x-3 to get rid of fraction
40= 8(2x-3)
Distribute 8
40= 16x-24
Add 24 to both sides
64=16x
Divide by 16
4=x
2) 2y-3/40=8
Multiply both sides by 40 to red rod of fraction
2y-3=320
Add 3 to both sides
2y= 323
Divide by 2
Y=323/2
Now just describe the differences in solving them
FYI / means fraction, right after the slash is bottom of fraction

The domain is x ≥ 1 as x cannot be less than 1 or else it'll become negative in square root which you cannot find a value.
Area of the rectangle is length x width
3x4=12
area of triangle is base x height divide by 2
2x4=8
8 divide by 2 is 4
add them all up
12 + 4 + 4 is 20