Q27 of 29 Page 3

Solve each of the following systems of equations by the method of cross–multiplication:

ax + by = a – b


bx – ay = a + b

Method of cross multiplication


a1x + b1y + c1 = 0


a2x + b2y + c2 = 0



This can be written as:


ax + by–(a–b) =0


bx – ay–(a+b)=0


So,


Here a1= a a2 = b


b1= b b2 = – a


c1= –(a – b) c2 = –(a + b)










⇒ x = 1 and y = –1


Hence values of x and y is 1,–1.


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