X+y = 4, therefore y = 4-x when you rearrange the equation.
You can subsitute this in: x-(4-x) = 6
-4+x = 6-x
x=10-x
2x = 10
x = 5
Substitute x into the previous equation:
5+y = 4
y = 4-5
y = -1
First we calculate the tax on the item:
11.4%($160) = 11.4(160)/100 = 18.24
hence the tax for the item is $18.24
The total price for the item would be:
160 + 18.24 = 178.24
hence the total price for the item including tax is:
$<span>178.24</span>
Using quadratic formula
x = [-18 +-sq root (324 -4 *3*15)] / 2*3
x = [-18 +-sq root (144)]/6
x1 = (-18 + 12) / 6 = -1
x2 = (-18 -12) / 6 = -30/6 = -5
