Look at the picture.

The perimeter of the triangle:
Simplify: 40y^3 - 8y^2 + 16y/8 y^2
40y^3 + -8y^2 + 2y^3
Combine terms: 40y^3 + -8y^2 + 2y^3
(40y^3 + 2y^3) + (-8y^2)
Answer: 42y^3 + -8y^2
Assuming you are asking
does -2x+y=6 and y-2x=4 have a solution
look at them
rewrite first equation by switching x and y
y-2x=6 and
y-2x=4
false since they are same values
there is no solution
these 2 lines are paralell
NO SOLUTION