Q5 of 71 Page 68

Solve the following pair of equations:

and x ≠ 1, y ≠ 2



Putting these value in given equations, we get


4a + 7b = 2, 2(10a + 14b) = 9


So, the given equations transforms into linear equation in two variables i.e.


4a + 7b = 2… (i)


20a + 28b = 9 …..(ii)


Multiply equation (i) by 4, so


16a + 28b = 8 … (iii)


20a + 28b = 9…..(ii)


Subtract (iii) from (ii),


20a + 28b – 16a – 28b = 9 – 8


⇒ 4a = 1



Putting above value in (i),



⇒ 7b = 2 – 1









⇒ y + 2 = 7


⇒ y = 5


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