Question

Solve the following sets of simultaneous equations.
 x + y = 4 ; 2x - 5y = 1

Answer 1

x + y = 4            .....(I)
2x - 5y = 1            .....(II)
From (I) we have
x = 4 - y
Putting this value of x in (II)
2 ( 4 - y ) - 5y = 1
⇒ 8 - 2y - 5y = 1
⇒ 8 - 7y = 1
⇒ 8 - 1 = 7y
⇒ 7 = 7y
⇒ y = 1.
Putting the value of y in (I) we have
x + 1 = 4
⇒ x = 3
Thus, ( x , y ) = ( 3,1 )