The student's error was in first step where he added -0.72 instead of 0.72
Step-by-step explanation:
Given equation;
z + (-0.72) = -2.5
When solving for z, eliminate the other numbers from one side.
Step 1: z + (−0.72) + (−0.72) = −2.5 + (−0.72)
In this step, the student should have added 0.72 because -0.72 was already present in the equation and to eliminate it, he should have add same number with opposite sign.
According to this Step, -0.72 and -0.72 would have been added, because according to mathematics, two numbers with minus sign are added and the sign remains same.
The student's error was in first step where he added -0.72 instead of 0.72
Keywords: addition, subtraction
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