Concept problem

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Can anybody help in understanding the logic behind this question??

Does the line y = ax + b pass through the point (2,5)?

(1) When it is reflected around the x-axis, the line passes through the point (1,-6).

(2) When it is reflected around the y-axis, the line passes through the point (-3,4)

What is the reflection concept??????

[Frankenstein]

Hi,
Any point (p,q) reflected in X- axis will become (p,-q)
Similarly (p,q) reflected in Y-axis becomes (-p,q)
From(1):
Line y = ax+b passes through (1,6)
Not sufficient
From(2):
Line y = ax+b passes through (3,4)
Not sufficient
Both(1) and (2) : line y = ax+b passes through (1,6) and (3,4). So, its equation is x+y = 7
(2,5) passes though this line.
Hence, C

[smackmartine]

Just giving you the concept :


Now try to solve this problem using this concept.
I will follow up if you find any difficulty.

[amit2k9]

well good question indeed.Liked this concept here.
the question asks for 5=2a+b ?


a (1,-6) = (1,6) in quadrant 1. line is 6= a+b. not sufficient.

b (3,-4) = (3,4) in quadrant 1. line is 4= 3a+b. not sufficient.

a+b gives

solving two equations above gives a=-1 and b=7

thus 5=2(-1) + 7. hence true.

C it is.