Answer: 
<u>Step-by-step explanation:</u>
Note the following identities: tan² x = sec²x - 1
tan² x + sec x = 1
(sec² x -1) + sec x = 1
sec² x + sec x - 2 = 0
(sec x + 2)(sec x - 1) = 0
sec x + 2 = 0 sec x - 1 = 0
sec x = -2 sec x = 1
20% have an A because 1/5 of 100 is 20
C + a = 140......a = 140 - c
5.3c + 9.4a = 1086.4
5.3c + 9.4(140 - c) = 1086.4
5.3c + 1316 - 9.4c = 1086.4
5.3c - 9.4c = 1086.4 - 1316
-4.1c = - 229.6
c = -229.6 / -4.1
c = 56......so their were 56 child tickets sold
Find the area of the rug by multiplying the length by the width:
7 x 5 = 35 square meters.
Now multiply the area of the rug by the cost:
35 square meters x 285 pesos per square meter = 9,975 total pesos.
The difference in elevation equals subtraction. In other words 39ft subtracted by 8ft equals 31ft. So New Orleans, Louisiana is 31ft ABOVE sea level compared to EL Centro, California.
