Equation 1 : 7x + 6y = 5xy
Equation 2 : 10x - 4y = 4xy
Dividing both equations by $$(xy)$$
=> $$\frac{7}{y} + \frac{6}{x} = 5$$
and $$\frac{10}{y}-\frac{4}{x} = 4$$
Let $$\frac{1}{y} = u$$ and $$\frac{1}{x} = v$$
=> $$7u+6v=5$$ ------------(iii)
and $$10u-4v=4$$ ------------(iv)
Multiplying equation (iv) by 3 and equation (iii) by 2 and adding them, we get :
=> $$(14u+30u) = (10+12)$$
=> $$u = \frac{22}{44} = \frac{1}{2}$$
Substituting it in equation (iv), => $$4v = 5 - 4 = 1$$
=> $$v = \frac{1}{4}$$
$$\therefore (x,y) = (4,2)$$
=> Ans - (C)
Create a FREE account and get: