Question

if a+b=76,a-b=38 then howmuch a & b

Answer 1

a+b = 76
a-b = 38

by adding the two equations,
2a = 76+38 = 114
⇒a = 114/2 = 57

a+b = 76
⇒57 + b = 76
⇒ b = 76 - 57 = 19

Answer 2

a + b = 76  consider  this as equation (1 )
a - b = 38 consider this as equation (2)
let equation (1 ) & (2 ) we get,
a + b = 76 
a - b = 38  (+ )
.................
2a = 114
a = 114/ 2
a = 57,
apply the value of a in any of those two equations to get the b value, 
let i take the equation (1 )
substitute a value in  equation 1 we get,
57 + b = 76 
b = 76 - 57 
b = 19
therefore a = 57 , b = 19, 
if u want to check whether the answers correct apply these two values in any of those equations 
let i take equation 2
a - b = 38 
57 - 19 = 38
38 = 38,
so the values are correct