Mathematics
If the point A(m, n) is first reflected in the y-axis and then reflected in the x-axis to the point A"(-10, 15), then the value of (m - n) is :
-25
-5
5
25
Reflection
3 Likes
Answer
Given, point A(m, n).
On reflection in y-axis, the sign of x-coordinate changes,
(m, n) ⇒ (-m, n)
On reflection in x-axis, the sign of y-coordinate changes,
(-m, n) ⇒ (-m, -n).
Given,
Final coordinates = A"(-10, 15)
∴ (-m, -n) = (-10, 15)
⇒ -m = -10 and -n = 15
⇒ m = 10 and n = -15
⇒ (m - n) = 10 - (-15) = 25.
Hence, Option 4 is the correct option.
Answered By
1 Like
Related Questions
If the point A(p, q) is first reflected in the y-axis and then reflected in the origin to the point A"(-6, 15), then the value of (2p + 3q) is :
-57
-21
43
57
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
Assertion (A): The point (0, 7) is invariant under the reflection in y-axis.
Reason (R): The image of a point P(x, y) when reflected in the y-axis is P'(x, -y).
Both A and R are true, and R is the correct explanation of A.
Both A and R are true, but R is not the correct explanation of A.
A is true, but R is false.
A is false, but R is true.
Assertion (A): The reflection of the point A(-4, 2) in the origin is the point A'(4, 2).
Reason (R): The image of a point P(x, y) when reflected in the origin is P'(-x, -y).
Both A and R are true, and R is the correct explanation of A.
Both A and R are true, but R is not the correct explanation of A.
A is true, but R is false.
A is false, but R is true.