Answer:
Option D (4, -5)
Step-by-step explanation:
This question can be solved by various methods. I will be using the hit and trial method. I will plug in all the options in the both the given equations and see if they balance simultaneously.
Checking Option 1 by plugging (-4, -5) in the first equation:
-2(-4) + 6(-5) = -38 implies 8 - 30 = -38 (not true).
Checking Option 2 by plugging (-5, 4) in the first equation:
-2(-5) + 6(4) = -38 implies 10 + 24 = -38 (not true).
Checking Option 3 by plugging (1, -6) in the second equation:
3(1) - 4(-6) = 32 implies 3 + 24 = 32 (not true).
Since all the options except Option 4 have been ruled out, therefore, (4,-5) is the correct answer!!!
306 is the total cards sent by all the students in the class. Lets say x is the number of students in class, therefore each student needs to send x-1 cards (since they do not send themselves a card). So depending on your level of math, you could either take the complex way to solve it using quadratic equations, or just find the number that if multiplied by itself then subtracted, gives you 306.
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Complex way
So a = 1, b = -1, c=-306
using the quadratic equation:
-3|2x + 6| = -12
|2x + 6| = -12/-3 = 4
2x + 6 = 4 and 2x + 6 = -4
2x = 4 - 6 and 2x = -4 - 6
2x = -2 and 2x = -10
x = -2/2 and x = -10/2
x = -1 and x = -5
The exact number of Pi is 3.14159265359.
