Question

co-ordinates of points of intersection of line ax+by=7 and bx+ay=5 is (3,1).find value of a and b

Answer 1

ax+by=7
a×3+b×1=7
3a+b=7 - (1)

bx+ay=5
b×3+a×1=5
3b+a=5
a+3b=5 - (2)

(1)×1 and (2)×3 and subtract
3a+b=7
3a+9b=15
-8b=-8
b=1

3a+b=7
3a+1=7
3a=6
a=2

a=2
b=1

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