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secondary 4 | A Maths
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Jona
Jona

secondary 4 chevron_right A Maths chevron_right Singapore

Pls help. Thank you

Date Posted: 3 years ago
Views: 222

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Ryan Patel
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115 answers (Tutor Details)
Eric Nicholas K
Eric Nicholas K
3 years ago
Not sufficient. Try drawing y = -x^2 + 6x - 2.

Correct is this.

Condition 1: a < 0
Condition 2: Discriminant < 0

36 - 4ac < 0
ac > 9

a must be negative AND the product ac must exceed 9.

We just have to find two negative values which multiply to become a giant number, like -2 and -10.
Eric Nicholas K
Eric Nicholas K
3 years ago
In your case, the two forms in (i) and (ii) which you have listed are not exactly equivalent (i.e. the "c" in both cases do not represent the same expression).