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anonymous
 one year ago
Madeline was completing the square, and her work is shown below. Identify the line where she made her mistake.
f(x) = 3x2 + 6x − 7
Line 1: f(x) = 3(x2 + 2x) − 7
Line 2: f(x) = 3(x2 + 2x + 1) − 7 − 1
Line 3: f(x) = 3(x + 1)2 − 8
Line 1
Line 2
Line 3
She did not make any mistakes
anonymous
 one year ago
Madeline was completing the square, and her work is shown below. Identify the line where she made her mistake. f(x) = 3x2 + 6x − 7 Line 1: f(x) = 3(x2 + 2x) − 7 Line 2: f(x) = 3(x2 + 2x + 1) − 7 − 1 Line 3: f(x) = 3(x + 1)2 − 8 Line 1 Line 2 Line 3 She did not make any mistakes

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anonymous
 one year ago
Best ResponseYou've already chosen the best response.0I think line 1 because it should be 3x on both sides not 2. but u should get a second opinion

zepdrix
 one year ago
Best ResponseYou've already chosen the best response.0Line 1 looks ok :) Madeline factored a 3 out of each of the first two terms.

zepdrix
 one year ago
Best ResponseYou've already chosen the best response.0To complete the square, she recognized that she needed a +1\[\large\rm f(x)=3(x^2+2x+1)7\]But you have to balance this by also subtracting 1. But the subtraction needs to happen inside of the brackets!\[\large\rm f(x)=3(x^2+2x+1\color{orangered}{1})7\]In order for this 1 to come outside of the brackets, it needs to multiply the 3.

zepdrix
 one year ago
Best ResponseYou've already chosen the best response.0\[\large\rm f(x)=3(x^2+2x+1)7\color{orangered}{3}\]\[\large\rm f(x)=3(x+1)^210\]Do you see where the mistake was made? :)
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