Answer:
c(3) is the largest
Step-by-step explanation:
For positive values of x, j(x) > a(x), so the comparison is between c(x) and j(x).
Without evaluating the functions, you can subtract 5x from them to get ...
c'(x) = c(x) -5x = 3x² +22
j'(x) = j(x) -5x = 7x
Now the question is whether c'(3) is larger than j'(3). The latter is ...
j'(3) = 7·3 = 21
Since c'(3) has an added constant of 22 and x² will be positive, we know that ...
c(3) > j(3) > a(3)
The function with the largest value at x=3 is c(x).
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You can, of course, simply evaluate the functions:
c(3) > j(3) > a(3) . . . . . . . c(3) is the largest
