Question

What are those two numbers whose sum is 58 and difference is 28?​

Answer 1

let the numbers be x and y.

According to the question,

x + y = 58 =≥ Equation 1

x - y = 28 =≥ Equation 2

Equation 1 :

x + y = 58

Transposing y to the RHS (Right Hand Side)

x = 58 - y

Therefore substituting the value for x as 58 - y in equation 2,

x - y = 28

(58 - y) - y = 28

By removing the brackets,

58 - y - y = 28

Adding like terms,

58 - 2y = 28

Transposing (-2y) to the RHS (Right Hand Side)

58 = 28 + 2y

Transposing 28 to the LHS (Left Hand Side),

58 - 28 = 2y

30 = 2y

$\dfrac{30}{2}$ = y

15 = y

Therefore x = 58 - 15 = 43

Verification :

x + y = 58

43 + 15 = 58

LHS = RHS

x - y = 28

43 - 15 = 28

LHS = RHS

Hence verified.