Eric Nicholas K's answer to Lee Meimei's Secondary 3 A Maths Singapore question.
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First question mistake, it should be ‘for all real values of k’, not ‘for all real values of x’, since x and y are the variables to be plotted on the graph.
Second mistake, when I used b2 - 4ac, I obtained 4k2 - 20k + 16 which can be factorised nicely into 4 (k - 4) (k - 1); the fact that it can be factorised means that there are indeed values of k for which b2 - 4ac = 0 and for which b2 - 4ac > 0.
In light of these two, there is indeed a question fault.
Just out of curiosity, which paper is this taken from?
Second mistake, when I used b2 - 4ac, I obtained 4k2 - 20k + 16 which can be factorised nicely into 4 (k - 4) (k - 1); the fact that it can be factorised means that there are indeed values of k for which b2 - 4ac = 0 and for which b2 - 4ac > 0.
In light of these two, there is indeed a question fault.
Just out of curiosity, which paper is this taken from?
Date Posted:
4 years ago
Unless k and y are to be plotted.
y = 4x + k
y + x2 = 2kx
If k is indeed a variable (and x can be set to any number), then the two equations reduces to a linear equation y = mk + c. For many values of x, the lines will intersect. So again, either way, the question is flawed.
y = 4x + k
y + x2 = 2kx
If k is indeed a variable (and x can be set to any number), then the two equations reduces to a linear equation y = mk + c. For many values of x, the lines will intersect. So again, either way, the question is flawed.
Chij sngs ca1
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