Solving Quadratic Equations using Complex Numbers

Solve by square root method

 $2x^2+2=34$  

• x = 4, -4

• x = 3, -3

• x = 5, -5

• x = 4

 $-\frac{x^2}{4}+3=19$  

•  $x=\pm i\sqrt{8}$  

•  $x=\pm8$  
  

•  $x=\pm8i$  

•  $x=8i$  

 $3\left(x+4\right)^2=81$  

•  $x=-4\pm3\sqrt{3}$  

•  $x=-4\pm9i$  

•  $x=-4\pm9\sqrt{3}$  

•  $x=-4\pm3i$  

Solve by the Square Root Method:

(x - 2) ² = 49

• 9 or -5

• ± 9

• ± 5

• ± 7

Determine the values of a, b, and c for the quadratic equation:

 $4x^2-8x-3=0$  

• a=4, b=-8, c=3

• a=4, b=-8, c=-3

• a=4, b=8, c=3

• a=4, b=8, c=-3

What should you do first in solving this equation?

 $x^2+6x-13=3$  

• Get factored form.

• Write down: a=1, b=6, c=-13

• Make it equal to 0 by subtracting 3 on each side.

• Type it all in a calculator.

Solve the following quadratic equation:

 $x^2+3x+2=0$  

• x = -1, x = -2

• x =1, x = 2

• x = -1, x = 2

• x = 1, x = -2

 $\left(3-4i\right)\left(5+6i\right)$  

• 39 +38i

•  $15\ -2i\ -24i^2$  

• 39 - 2i

• 9 - 2i

Add. (-7 + 9i) + (2 - 10i)

• -5 + i

• -9 + i

• -5 - i

• 9 - i

Subtract. (4 - 2i) - (3 + 6i)

• 7 - 4i

• 1 + 4i

• 1 - 8i

• 7 - 8i