- #1
tomwilliam2
- 117
- 2
Homework Statement
My son (aged 13) received his math test back, and got the following problem wrong:
Which of the following functions is linear?
A: f(x) = -3x + 5
B: g(x) = x^2
C: h(x) = 6x - (1/2)
D: p(x) = 4x/5
The attempt at a solution
He answered B, which is clearly wrong, but it wasn't clear to me why D was supposed to be the right answer. I would have though A and C were also linear. According to his textbook, those are affine functions, and a linear function has to go through the origin. Is this right?
The following website seems to confirm it, but I've always been taught that a linear function is any function where Delta Y / Delta X = constant.
http://www.math.ubc.ca/~cass/courses/m309-03a/a1/olafson/affine_fuctions.htm
Edit: I just found the test and changed the values in it, which doesn't affect the question
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