So we have 2 variables here: tacos and orders of nachos.
When we translate the paragraphs into equation:

Now, in this situation we can make use the elimination method by converting 3n to -27n.

Add both equations:

So we find that one taco costs $2.75.
We can plug this into any of the first two equations to find n:

So one order of nachos cost $1.40.
Answer:
im pertty sure $740
Step-by-step explanation:
We presume the temperature is decreasing at midnight, so reaches a low at 6 a.m.. The amplitude of the variation is (87-63)/2 = 12 degrees. We want the period to be 24 hours, so the argument of the sine function will be 2π(t/24) = πt/12. Then we can write
... d = 75-12sin(π·t/12)
Answer:
Adults = x
Students = y = x + 40. 40 more student than adult
Adult = $8, Student = $6
Total for Adults = 8*x = 8x
Total for students = 6*y = 6y
Total = $1920
8x + 6y = 1920
Hence system of equations are:
y = x + 40
8x + 6y = 1920