21x - 27y = 111; 27x - 21y = 129
Answers
Answer :
x = 4 , y = -1
Solution :
Here ,
The given equations are ;
21x - 27y = 111 --------(1)
27x - 21y = 129 ---------(2)
Now ,
Adding eq-(1) and (2) , we have ;
=> 21x - 27y + 27x - 21y = 111 + 129
=> 48x - 48y = 240
=> 48(x - y) = 240
=> x - y = 240/48
=> x - y = 5 ----------(3)
Now ,
Subtracting eq-(1) from (2) , we have ;
=> (27x - 21y) - (21x - 27y) = 129 - 111
=> 27x - 21y - 21x + 27y = 18
=> 6x + 6y = 18
=> 6(x + y) = 18
=> x + y = 18/6
=> x + y = 3 ----------(4)
Now ,
Adding eq-(3) and (4) , we have ;
=> x - y + x + y = 5 + 3
=> 2x = 8
=> x = 8/2
=> x = 4
Now ,
Putting x = 4 in eq-(4) , we have ;
=> x + y = 3
=> 4 + y = 3
=> y = 3 - 4
=> y = -1
Hence ; x = 4 , y = -1 .
Answer:x = 4 , y = -1
Step-by-step explanation:
Here ,The given equations are ;
21x - 27y = 111 --------(1)
27x - 21y = 129 ---------(2)
Now ,
Adding eq-(1) and (2) , we have ;
=> 21x - 27y + 27x - 21y = 111 + 129
=> 48x - 48y = 240
=> 48(x - y) = 240
=> x - y = 240/48
=> x - y = 5 ----------(3)
Now ,
Subtracting eq-(1) from (2) , we have ;
=> (27x - 21y) - (21x - 27y) = 129 - 111
=> 27x - 21y - 21x + 27y = 18
=> 6x + 6y = 18
=> 6(x + y) = 18
=> x + y = 18/6
=> x + y = 3 ----------(4)
Now ,
Adding eq-(3) and (4) , we have ;
=> x - y + x + y = 5 + 3
=> 2x = 8
=> x = 8/2
=> x = 4
Now ,
Putting x = 4 in eq-(4) , we have ;
=> x + y = 3
=> 4 + y = 3
=> y = 3 - 4
=> y = -1