SOLUTION: Bill and Jenna are solving the quadratic equation x^2 - x = 12. Bill solved this way x^2 - x = 12 x(x - 1) = 12 x = 12 or 13 Jenna solved this way x^2 - x =

Algebra ->  Functions -> SOLUTION: Bill and Jenna are solving the quadratic equation x^2 - x = 12. Bill solved this way x^2 - x = 12 x(x - 1) = 12 x = 12 or 13 Jenna solved this way x^2 - x =       Log On


   

Question 958024: Bill and Jenna are solving the quadratic equation x^2 - x = 12.
Bill solved this way
x^2 - x = 12
x(x - 1) = 12
x = 12 or 13
Jenna solved this way
x^2 - x = 12
x^2 - x - 12 = 0
(x - 4)(x + 3) = 0
x = 4 or x = -3
Which student is correct?
What error did the other student make when solving?

Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
Bill is incorrect
Jenna is correct

Bill used the zero product property wrong. He needs to have the equation in the form A*B = 0. The right side must be 0 for it to work.

Jenna did it correctly because (x - 4)(x + 3) = 0 is indeed in the form A*B = 0 where A = x-4 and B = x+3. Setting each expression equal to zero and solving each sub-equation leads to the correct answers.

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