Mathematics
If the point P(a, b) is reflected in the x-axis to P'(3, -7), then the value of (a - b) is :
10
-10
4
-4
Answer
Given,
Co-ordinates of point P = (a, b) and P' = (3, -7).
We know that,
On reflecting in x-axis, the sign of y co-ordinate changes.
∴ (a, b) ⇒ (a, -b)
Given,
P(a, b) is reflected in the x-axis to P'(3, -7).
∴ (a, -b) = (3, -7)
⇒ a = 3 and -b = -7
⇒ a = 3 and b = 7.
Thus, a - b = 3 - 7 = -4.
Hence, Option 4 is the correct option.
Related Questions
The point P(-14, -18) is reflected in origin and after that reflected in x-axis. The co-ordinates of the image of point P are :
(-14, -18)
(14, -18)
(-14, 18)
(14, 18)
The point P(-7, 13) is reflected in origin followed by reflection in y-axis. The co-ordinates of the image of point P are :
(7, 13)
(-7, -13)
(7, -13)
(-7, 13)
If the point P(a, b) is reflected in the y-axis to P'(-3, -9), then the value of (a + b) is :
-6
6
-15
-12
If the point P(a, b) is reflected in the origin to P'(7, -13), then the value of (a - b) is :
20
6
-20
-6