You'd do $500 x 0.15 to which gives you 75$ in tax. $500 + $75 = $575 selling price
4x - y = 5 --> 4x = y + 5
substitute
4x + 4y = -4
(y + 5) + 4y = -4
5y + 5 = -4
5y = -9
y = -1.8
solve x
4x = y + 5 = -1.8 + 5 = 3.2
x = 3.2/4 = 0.8
Lets take away 2 white chips...
8 black and 4 white...total of 12 chips
P(black) = 8/12 = 2/3
remove 2 white chips <==
Collect like terms
2n2 i’m gonna assume is 2n^2
and n2 is 2n
2n^2-10n+5