Question

n/5-5/7=2/3 find the n

Answer 1

n/5 - 5/7 = 2/3
⇒ (7n-25)/35 = 2/3
⇒ (7n-25) = 2/3×35
⇒ (7n-25) = 70/3
⇒ 7n = 70/3 + 25
⇒ 7n = (70+75)/3
⇒ 7n = 145/3
⇒ n = 145/3×7
⇒ n = 145/21 .
 
Check : 
n/5 - 5/7 = 2/3 
⇒(145/21)/5 - 5/7 = 2/3
⇒ 145/105 - 5/7 = 2/3
⇒ (145-75)/105 = 2/3
⇒ 70/105 = 2/3
⇒ 10/15 = 2/3
⇒ 2/3 = 2/3
Therefore , L.H.S = R.H.S . 

Answer 2

n/5-5/7=2/3
2/3+5/7=n/5
5(2/3+5/7)=n

ans: n=5(2/3+5/7)