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
Length of circumference is 2πr
2 π r and r is equal to 2 cm
I.e 12.5 cm
From the cars parked in the lot he will earn (40)($10)=$400, but he will need to pay $50 for the rent. Thus his total $ earned will be $400-$50=$350.
D-7<span>≤ 3
add 7 to both sides
d</span><span>≤10</span>
