Home > A2C > Chapter 9 > Lesson 9.2.2 > Problem 9-91
9-91.
Decide which of the following equations have real roots, and which have complex roots without completely solving them. Homework Help ✎
y = x2 − 6
y = x2 + 6
y = x2 − 2x + 10
y = x2 − 2x − 10
y = (x − 3)2 − 4
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).