Question
Mathematics Question on Relations and functions
If [2x+y4x5x−74x]=[77y−13yx+6], then x+y=
A
(A) 3
B
(B) 4
C
(C) 5
D
(D) 6
Answer
(C) 5
Explanation
Solution
Explanation:
As we know,When two matrices are equal, all the corresponding elements must be equal.Given,[2x+y4x5x−74x]=[77y−13yx+6]Comparing two elements of first column,2x+y=7⇒y=7−2x...(1)5x−7=y...(2)Compairing value of y from equation (1) and (2) we get,7−2x=5x−7⇒7+7=5x+2x⇒14=7x∴x=2Putting value of x in equation (1), we gety=7−2×2⇒y=7−4⇒y=3Now, x+y=2+3=5So, the value of x+y is 5.Hence, the correct option is (C).