Q52 of 54 Page 77

Solve for x and y : ; .

Let xy = a


5a = x + y ……(1)



7a = x – y ……(2)


Add (1) and (2)


7a + 5a = x – y + x + y


12a = 2x ÷ 2


6a = x


6xy = x (because a = xy)


6y = 1



Put value of y in (2)


7xy = x – y




7x = 6x – 1


7x – 6x = – 1


x = – 1


More from this chapter

All 54 →
50

and ax + by = a2 + b2. Solve for x and y.

 51

Solve the following pair of linear equations: 21x + 47y = 110 and 47x + 21y = 162

 53

Solve for x and y: x + 4y = 27xy & amp; x + 2y = 21xy

 54

Solve the following pair of equations - : 47x + 31y = 63 and 31x + 47y = 15.