Q1 of 71 Page 65

Solve the following pairs of equations by cross multiplication method:

, 7x— 15y = 21

Given equations are


, 7x— 15y = 21


Change the given equations to the form,


a1x + b1y + c1 = 0 and a2x + b2y + c2 = 0 …(i)


⇒


And7x — 15y – 21 = 0


⇒ 5x + 3y – 15 = 0 and 7x — 15y – 21 = 0


On comparing with (i) we get,


a1 = 5, b1 = 3, c1 = – 15; a2 = 7, b2 = – 15, c2 = – 21


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, 0).


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