Section C Section C Checkpoint

Problem 1

Complete the square to solve the equations. Give exact solutions.

  1. x2+2x=3x^2 + 2x = 3
  2. x2+6x+3=0x^2 + 6x + 3 =0
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Solution
  1. x=1x = 1 and x=-3x = \text{-}3. Sample reasoning: Completing the square leads to (x+1)2=4(x+1)^2 = 4. This means that x+1=2x + 1 = 2 and x+1=-2x + 1 = \text{-}2.
  2. x=-3±6x = \text{-}3\pm\sqrt{6}. Sample reasoning: Completing the square leads to (x+3)2=6(x+3)^2 = 6. This means that x+3=±6x + 3 = \pm \sqrt{6}.
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Sample Response
  1. x=1x = 1 and x=-3x = \text{-}3. Sample reasoning: Completing the square leads to (x+1)2=4(x+1)^2 = 4. This means that x+1=2x + 1 = 2 and x+1=-2x + 1 = \text{-}2.
  2. x=-3±6x = \text{-}3\pm\sqrt{6}. Sample reasoning: Completing the square leads to (x+3)2=6(x+3)^2 = 6. This means that x+3=±6x + 3 = \pm \sqrt{6}.

Problem 2

Select all of the equations that are equivalent to x=3±2x = 3 \pm \sqrt{2}.
A
x=5x = \sqrt{5}
B
x=-1x = \sqrt{\text{-}1}
C
x=3+2x = 3 + \sqrt{2}
D
x=±6x = \sqrt{\pm 6}
E
x=32x = 3 - \sqrt{2}
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Solution
C, E
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Sample Response
C, E