Okay. You can decompose 749 with these ways:
700 + 40 + 9
or
500 + 200 + 40 + 9
So you will need to solve for x and y before evaluating 2x+y....
2x-y=9, y=2x-9 now this will make 4x^2-y^2=171 become:
4x^2-(2x-9)^2=171
4x^2-(4x^2-36x+81)=171
36x-81=171
36x=252
x=7, now we can use 2x-y=9 to solve for y...
2(7)-y=9
14-y=9
-y=-5
y=5
now we know that x=7 and y=5, 2x+y becomes:
2(7)+5
14+5
19
$52.50 / 42 = 1.25
$1.25 per each slice
If its nonsense question well i don't know
please don't give nonsense question.