Jack's answer to glittr's Secondary 3 A Maths Singapore question.

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Jack
Jack's answer
37 answers (A Helpful Person)
1st
Don't know why my answer is abit different from the question, but the method should be the same. An equation has no solution (no real roots) when b^2-4ac<0 as it cannot be square rooted. (based on quadratic equation)
Eric Nicholas K
Eric Nicholas K
4 years ago
I have verified from the Desmos application that k is indeed > 0.75.
J
J
4 years ago
discriminant b² - 4ac = 9 - 12k

If k > 0.5,

-k < -0.5

-12k < -6

9 - 12k < 9 - 6

9 - 12k < 3

So it would be possible for real solutions to exist if k > 0.5. k needs to be > 0.75 for no real solutions to exist
glittr
Glittr
4 years ago
thanks y’all are correct , i wrote 0.5 wrongly . it should have been 0.75