Answer: x= -6; y= -1
Step-by-step explanation:
-4x + y = 23
4x - 9y = - 15
-4x + y = 23
y = 23 + 4x [Add 4x to both side]
4x - 9(23 + 4x) = - 15
4x - 207 - 36x = - 15
-32x - 207 = -15
-32x = 192 [Add 207 to both side]
x = -6 [Divide -32 from both side]
-4x + y = 23
-4(-6) + y = 23 [Plug in -6 for x]
24 + y = 23 [Subtract 24 from both side]
y = -1
A single drink would cost be $1.55. This is because:
13 + 4x - 6 = 13.20.
(13.20 - 13 + 6) = 6.20.
6.20 / 4 = 1.55
Hope this helped.
9x2-1............................................................................
