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i need a little help. please use evidence and steps leading to answer. I asks to find the error in one or more of the steps and explain why its wrong

i need a little help. please use evidence and steps leading to answer. I asks to find-example-1
User Saeid Amini
by
2.6k points

1 Answer

19 votes
19 votes

To identify the error in the procedure shown in the picture, it is important to remember the following:


\begin{gathered} (a+b)^2=a^2+2ab+b^2 \\ (a-b)^2=a^2-2ab+b^2 \end{gathered}

Keeping this on mind, you can solve the given equation as following:

1. Given:


\sqrt[]{5x}=x+2

2. Square both sides of the equation:


\begin{gathered} (\sqrt[]{5x})^2=(x+2)^2 \\ 5x=x^2+2(x)(2)+2^2 \\ 5x=x^2+4x+4 \end{gathered}

3. Move the the term on the left side to the right side and add like terms:


0=x^2-x+4

4. Apply the Quadratic formula to find "x":


\begin{gathered} x=\frac{-b\pm\sqrt[]{b^2-4ac}}{2a} \\ \\ x=\frac{-(-1)\pm\sqrt[]{(-1)^2-4(1)(4)}}{2(1)} \\ \\ x_1=(1)/(2)(i-\sqrt[]{15)} \\ \\ x_2=(1)/(2)(i+\sqrt[]{15)}_{} \end{gathered}

Therefore, you can identify that the error is in Step C, because:


(x+2)^2=x^2+4x+4

User Shahryar Rafique
by
2.5k points