Mathematics
If the point A(m, n) is first reflected in the x-axis and then reflected in the y-axis to the point A"(-12, -18), then the value of (2m - n) is :
6
-6
-30
30
Reflection
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Answer
Given, point A(m, n).
On reflection in x-axis, the sign of y-coordinate changes,
(m, n) ⇒ (m, -n)
On reflection in y-axis, the sign of x-coordinate changes,
(m, -n) ⇒ (-m, -n).
Given,
Final coordinates = A"(-12, -18)
∴ (-m, -n) = (-12, -18)
⇒ -m = -12 and -n = -18
⇒ m = 12 and n = 18
⇒ 2m - n = 2(12) - 18
⇒ 24 - 18
⇒ 6.
Hence, Option 1 is the correct option.
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