Sketching quadratics

Maths

Quadratic expressions (9.9)

Select the words that best fill in the gaps in order: The __________ is where the curve crosses the y axis, when _______.

What are the coordinates of where y= x² + 14x + 24 crosses the y axis?

Where does y = x² - 3x - 10 cross the y axis?

Which graph could be a sketch of y=(x+4)(x-3)?

Which graph could be a sketch of -x² + 3x - 2? *Hint* Try out some coordinates to check!

Zaki is correct, the curve will never cross either axes.

Zaki is incorrect the curve wil cross the x axis only.

Zaki is incorrect the curve will cross BOTH axes.

Zaki is incorrect the curve will cross the y axis only.

Zaki says y = x² + 1 will never cross either axes. Is that correct?

Fill in the gap: ________ is the opposite of expanding.

No, Cala is incorrect, there DOES exist a pair of factors of 8 that add to give a negative number.

Yes, Cala is correct, there DOES NOT exist a pair of factors of 8 that add to give a negative number.

Cala says that you cannot factorise x² -9x + 8 because there does not exist a pair of factors for 8 that add to give a negative number. Is she correct?

A quadratic expression  x² + bx - 20 can be factorised. Find all the possible values for b when b is negative.

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Sketching quadratics

Lesson outcome