Solving Quadratics with Complex Roots

When you are solving for the roots/zeros of a quadratic function, which equation should you use?

• $D=b^2-4ac$

• $x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}$

Tags

CCSS.HSA-REI.B.4B

Solve for x:

• x = {-3+2i, -3-2i}
• x = {7, 6}
• x = 2±i√3
• No solution

Tags

CCSS.HSA-REI.B.4B

CCSS.HSN.CN.C.7

Solve for x: x² - 5x + 8 = 0

• x = (-5±i√7)/2
• x = (5±i√7)/2
• x = (8±i√7)/2
• x = (5±√57)/2

Tags

CCSS.HSA-REI.B.4B

CCSS.HSN.CN.C.7

Solve for x: 3x² - 6x + 6 = 0

• x = 1± i
• x = 3, -6
• x = 4.8, 2.7
• Undefined

Tags

CCSS.HSA-REI.B.4B

CCSS.HSN.CN.C.7

Find the roots of the following quadratics:

 $2x^2+6x=11$  

•  $\left\{\frac{11}{2},8\right\}$  

•  $\left\{-2\sqrt{31},\ -\sqrt{31}\right\}$  

•  $\left\{\frac{-3+\sqrt{31}}{2},\ \frac{-3-\sqrt{31}}{2}\right\}$  

• No Solutions

Tags

CCSS.HSA-REI.B.4B

Solve x² - 5x + 10 = 0

• (5 - i√15)/2  ,  (5 + i√15)/2
• (5 - √15)/2  ,  (5 + √15)/2
• (5 - i√65)/2  ,  (5 + i√65)/2
• (5 - √65)/2  ,  (5 + √65)/2

Tags

CCSS.HSA-REI.B.4B

CCSS.HSN.CN.C.7

Which is a solution to x² - 4x + 5 = 0

• 2 + i
• 2i
• 2 - 2i
• -2 - i

Tags

CCSS.HSA-REI.B.4B

CCSS.HSN.CN.C.7

What are the zeros of the function f(x) = x² + 64?

• -8 and 8
• -8i and 8i
• (-√8) i and (√8) i
• -√8  and √8

Tags

CCSS.HSN.CN.C.9

Solve x² - 5x + 10 = 0

• (5 - i√15)/2  ,  (5 + i√15)/2
• (5 - √15)/2  ,  (5 + √15)/2
• (5 - i√65)/2  ,  (5 + i√65)/2
• (5 - √65)/2  ,  (5 + √65)/2

Tags

CCSS.HSA-REI.B.4B

CCSS.HSN.CN.C.7