Which of these statements is correct?
Tick one box - AQA - A-Level Maths Mechanics - Question 1 - 2018 - Paper 2
Question 1
Which of these statements is correct?
Tick one box.
$x = 2 herefore x^2 = 4$
$x^2 = 4 herefore x = 2$
$x^2 = 4 herefore x = 2$
$x^2 = 4 herefore x = -2$
Worked Solution & Example Answer:Which of these statements is correct?
Tick one box - AQA - A-Level Maths Mechanics - Question 1 - 2018 - Paper 2
Step 1
$x = 2 herefore x^2 = 4$
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Answer
This statement is correct because if x=2, then squaring both sides gives x2=22=4. Hence, this is a true implication.
Step 2
$x^2 = 4 herefore x = 2$
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Answer
This statement is incorrect because solving x2=4 gives two possible solutions: x=2 and x=−2. Therefore, this implication does not hold true.
Step 3
$x^2 = 4 herefore x = 2$
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Answer
Similar to the previous point, this statement is also incorrect for the same reason: x2=4 results in x=2 and x=−2.
Step 4
$x^2 = 4 herefore x = -2$
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Answer
This statement is misleading as it suggests that the only solution is x=−2, which is also incorrect. The equation x2=4 indicates both solutions, x=2 and x=−2.
