Q1 of 71 Page 65

Solve the following pairs of equations by cross multiplication method:

3x + y = 5, 5x + 3y = 3

Given equations are


3x + y = 5, 5x + 3y = 3


Change the given equations to the form, a1x + b1y + c1 = 0 and a2x + b2y + c2 = 0 …(i)


⇒ 3x + y – 5 = 0 and


5x + 3y – 3 = 0


On comparing with (i) we get,


a1 = 3, b1 = 1, c1 = – 5; a2 = 5, b2 = 3, c2 = – 3


Applying cross multiplication method which says,



Putting the given values in the above equation we get,







Similarly,



∴The solution of the pair of equations is (3, – 4).


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