You need to cut the shape into other shapes that you know the formula off
We know the y intercept is 16 because y=16 when x=0.
Find slope by calculating change in y over change in x.
(12-16)/(2-0)
-4/2
-2
Plug both values into slope intercept form. y=mx+b where m is slope and b is the y intercept.
Final answer: y=-2x+16
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:

No, they do not have a pattern nor do they flow to get her the difference between 6 and 11 is 5, whereas the difference between 11 and 17 is 6.
Answer: x=114
Step-by-step explanation: