Elimination:
-4x+y=6
-5x-y=21 ...and then u add them together so its;
(the y cancelled out so its 0) x =27
plug in the 27 to any x...
-4(27) + y = 6
-108+y=6
add -108 on both sides so its...
y= -102
(27, -102)
Hope this helped :)
Answer:
f( - 2) = 23
Step-by-step explanation:

Time is 4 hrs., coffee is 0 cups. Point (4,0)
So A
N(1/5) = (2/15)
divide both sides by (1/5)
n = (2/15)/(1/5)
to divide fractions, cross multiply, e.g. (2*5)/(15*1) = 10/15
n = 10/15 = 2/3 or 0.666666.