Question 4 - Mind the Mistake, Mend the Mistake - Chapter 7 Class 7 - Finding the Unknown (Ganita Prakash II)

Transcript

Question 4 The following are some equations along with the steps used to solve them to find the value of the letter−number. Go through each solution and decide whether the steps are correct. If there is a mistake, describe the mistake, correct it and solve the equation.Is there a mistake? Yes What went wrong? The student messed up the signs when moving terms. Moving +3z to the left should make it -3z. Moving +2 to the right should make it -2. Correct solution Now, 5z + 2 = 3z – 4 Taking 2 on right side, it becomes subtraction 5z = 3z – 4 – 2 5z = 3z – (4 + 2) 5z = 3z – 6 Taking 3z on left side, it becomes subtraction 5z – 3z = –6 2z = –6 Taking 2 on right side, it becomes division z = (−6)/2 z = –3