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# Range of y=x(x-6) ? watch

1. x E R (real number)

The answer given is equal to or more than -9

Any pointers as to how you reach that conclusion?

Thanks
2. (Original post by buj)
x E R (real number)

The answer given is equal to or more than -9

Any pointers as to how you reach that conclusion?

Thanks
What does the range of a function mean?

If you draw the graph, you should be able to see why it's -9 or greater.
3. ok find the minimum point using differentiation. i get it. thanks guys.
4. You could also do it by completing the square:

x^2 - 6x = (x-3)^2 - 9

So the minimum value has to be -9 since (x-3)^2 has to be greater than or equal to 0.

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