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Maths C1 Question

Hi,

Bit confused with this C1 question - can someone check if I've done it right/tell me how to do it?

The question is:

Show, either by calculating the discriminant or by completing the square, that x^2 - 8x + 20 is never zero

So I calculated the discriminant via b^2 - 4ac which equals 64-80 = -16

So does that mean it has no real roots, hence why it can't be zero? I was a bit confused as the question didn't state whether the equation=0

Thanks a lot!

Reply 1

spurs9393

Wait... Do you complete the square to get (X-4)^2 + 4, and that means whatever X is you will always have to add 4 so the answer can never be zero?

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