Mathematics
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
Reflection
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Answer
Given,
Coordinates of P(a, b) and P'(-3, -9).
We know that,
On reflecting in y-axis the sign of x co-ordinate changes.
∴ (a, b) ⇒ (-a, b)
Given,
P(a, b) is reflected in the y-axis to P'(-3, -9)
∴ (-3, -9) = (-a, b)
⇒ -a = -3 and b = -9
⇒ a = 3 and b = -9.
∴ a + b = 3 + (-9) = 3 - 9 = -6.
Hence, Option 1 is the correct option.
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