Solve for x and y:
71x + 37y = 253,
37x + 71y = 287.
We have,
71x + 37y = 253 …(i)
37x + 71y = 287 …(ii)
To solve these equations, we need to simplify them.
So, by adding equations (i) and (ii), we get
(71x + 37y) + (37x + 71y) = 253 + 287
⇒ (71x + 37x) + (37y + 71y) = 540
⇒ 108x + 108y = 540
Now dividing it by 108, we get
x + y = 5 …(iii)
Similarly, subtracting equations (i) and(ii),
(71x + 37y) – (37x + 71y) = 253 – 287
⇒ (71x – 37x) + (37y – 71y) = - 34
⇒ 34x – 34y = - 34
Dividing the equation by 34, we get
x – y = - 1 …(iv)
To solve equations (iii) and (iv), we need to make one of the variables (in both the equations) have same coefficient.
Here the variables x & y in both the equations have same coefficients.
⇒ 2x = 4
⇒ x = 2
Substitute x = 2 in eq.(iii)/eq.(iv), as per convenience of solving.
Thus, substituting in eq.(iii), we get
2 + y = 5
⇒ y = 3
Hence, we have x = 2 and y = 3.