Answer:

17, 10 and 22

Step-by-step explanation:

Let the sides are a , b and c. Here,

first side = a = 7 more than b = 5 less than c

  ⇒ a = 7 + b = c - 5

⇒ a - 7 = b       &     a + 5 = c

 Given,

⇒ Perimeter = 49

⇒ Sum of all sides = 49

⇒ a + ( a - 7 ) + ( a + 5 ) = 49

⇒ a + a - 7 + a + 5 = 49

⇒ 3a - 2 = 49

⇒ 3a = 49 + 2 = 51

⇒ a = 51/3 = 17

   Hence sides are :

a = 17

a - 7 = 17 - 7 = 10

a + 5 = 17 + 5 = 22