Q1 of 71 Page 65

Solve the following pairs of equations by cross multiplication method:

0.3x + 0.4y = 2.5 and 0.5x — 0.3y = 0.3

Given equations are


0.3x + 0.4y = 2.5 and 0.5x — 0.3y = 0.3


Change the given equations to the form,


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


⇒ 0.3x + 0.4y – 2.5 = 0 and


0.5x — 0.3y – 0.3 = 0


On comparing with (i) we get,


a1 = 0.3, b1 = 0.4, c1 = – 2.5; a2 = 0.5, b2 = – 0.3, c2 = – 0.3


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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