Unit test Problem Becky tried to evaluate an expression step by step. \quad\begin{aligned} &\dfrac{4}{5} +7 -\dfrac{5}{4} \\ =&\dfrac{4}{5} -\dfrac{5}{4}+7&\green{\text{Step } 1} \\ \\ =&0+7&\blue{\text{Step } 2} \\ \\ =&7&\purple{\text{Step } 3} \\ \\ \end{aligned} = = = 5 4 +7− 4 5 5 4 − 4 5 +7 0+7 7 Step 1 Step 2 Step 3 Find Becky's mistake.

Becky's mistake was that she said , while it's actually equal to .

Step-by-step explanation:

Step 1 looks fine as she just rearranged the equation, keeping the negatives and positives right.

Step 2 is where she said that  . This would only be true if we were multiplying one of the numbers by 0. So Step 2 was wrong.

Step 3 is right, as 0+7 = 7.

Hope this helped!

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Step-by-step explanation: