NCERT Solutions for Class 8 Maths Chapter 9 Algebraic Expressions and Identities Exercise 9.5

Ques. If the perimeter of the triangle is given by the algebraic equation- 8y² – 9y + 4. The two sides are given by the expression- 3y² – 5y and 4y² + 12. Find the third side of the triangle.

Soln: The perimeter of the triangle = Sum of all sides of the triangle

Therefore,

Third side = Perimeter of the triangle – Sum of the other two sides

Applying the terms in the equation, we get,

= (8y² – 9y + 4) – (3y²– 5y + 4y² + 12)

= (8y² – 9y + 4) – (7y² – 5y + 12)

= 8y² – 9y + 4 – 7y² + 5y – 12

= y² – 4y – 8