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34 votes
34 votes
12. Iquolese solved the equation using the steps below.3x + 11 = 100+ x + 13x + 100 = x + 123x = x+882x = 88x = 44Which statement describes Iquolese's first mistake?A-From step 2 to step 3 Iquolese should have added 1x to get 4x = 88.B-From the given to step 1 Iquolese should have combined like terms on each side of the equationto get 3x + 11 = 101 + x.C-From step 3 to step 4 Iquolese should have multiplied by 2 to get x = 176.D-From step 1 to step 2 Iquolese should have added 100 to get 3x = x + 112.

User Alvaro Lorente
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1 Answer

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27 votes

B-From the given to step 1 Iquolese should have combined like terms on each side of the equation

to get 3x + 11 = 101 + x.

1) First of all, the best way to tackle questions like this is to solve the equation properly and then check the mistakes Iquolese has done.


\begin{gathered} 3x+11=100+x+1 \\ \\ 3x+11=x+101 \\ \\ 3x+11-11=x+101-11 \\ \\ 3x=x+90 \\ \\ 3x-x=x-x+90 \\ \\ 2x=90 \\ \\ (2x)/(2)=(90)/(2) \\ \\ x=45 \end{gathered}

Note that all we did was isolate the x-terms on the left side and then add/subtract from that.

2) Now, we can pay closer attention to Iquolese's steps. Comparing Iquolese's job to ours we can tell the answer is:

B-From the given to step 1 Iquolese should have combined like terms on each side of the equation

to get 3x + 11 = 101 + x.

User Alexander Mamutov
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2.8k points