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Home > A2C > Chapter 9 > Lesson 9.2.2 > Problem 9-91

9-91.
  1. Decide which of the following equations have real roots, and which have complex roots without completely solving them. Homework Help ✎

    1. y = x2 − 6

    2. y = x2 + 6

    3. y = x2 − 2x + 10

    4. y = x2 − 2x − 10

    5. y = (x − 3)2 − 4

    6. y = (x − 3)2 + 4

Find the discriminant.

b2 − 4ac = 02 − 4(1)(−6) = 24

This equation has real roots.

b2 − 4ac = 02 − 4(1)(6) = −24

This equation has complex roots.

See part (b).

This equation has complex roots.

See part (a).

Find the vertex.
Is it above or below the x-axis?

See part (e).