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Question 167407: A student is asked to solve the equation
x^2 +x - 6 = 5
The student gives the following steps:
(x - 2)(x + 3) = 5
(x - 2) = 5 (x + 3) = 5
x = 7 x = 2
Explain whether or not this is correct, and make any necessary corrections.
Please help me with this one.
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! A student is asked to solve the equation
x^2 +x - 6 = 5
The student gives the following steps:
(x - 2)(x + 3) = 5
The next step is wrong. There is no rea-1son to think
that the factors each equal 5.
(x - 2) = 5 (x + 3) = 5
x = 7 x = 2
Explain whether or not this is correct, and make any necessary corrections.
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Correct procedures:
x^2 +x - 6 = 5
x^2 +x -11 = 0
x = [-1 +- sqrt(1-4*1*-11)]/2
x = [-1 +- sqrt(45)]/2
x = [-1 +- 3sqrt(5)]/2
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Cheers,
Stan H.
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