CBSE Notes, Lectures

CBSE - Mathematics - Polynomials

Polynomials

NCERT Exercise Exercise 2.5

Give possible expressions for the length and breadth of each of the following rectangles, in which their areas are given: 

Give possible expressions for the length and breadth of each of the following rectangles, in which their areas are given: 
(i) Area : 25a2 - 35a + 12
(ii) Area : 35 y2 + 13y - 12

Answer


(i) Area : 25a2 - 35a + 12

Since, area is product of length and breadth therefore by factorizing the given area, we can know the length and breadth of rectangle.
25a2 - 35a + 12
25a2 - 15a -20a + 12
= 5a(5a - 3) - 4(5a - 3)
(5a - 4)(5a - 3)
Possible expression for length = 5a - 4
Possible expression for breadth = 5a - 3

(ii) Area : 35 y2 + 13y - 12
35 y2 + 13y - 12
35y2 - 15y + 28y - 12
= 5y(7y - 3) + 4(7y - 3)
(5y + 4)(7y - 3)
Possible expression for length = (5y + 4)
Possible expression for breadth (7y - 3)

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