CTET 2 Math and Science Sep 2015 Paper

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Question : 36 of 120

Marks: +1, -0

In the product of

(5x + 2)

and

(2x^2 – 3x + 5)

, the sum of the coefficients of x2 and x is :

8
9
–8
–9

Solution:

Product

=(5x+2)(2x^{2}-3x+5)

=5x(2x^{2}-3x+5)+2(2x^{2}-3x+5)

=10x^{3}-15x^{2}+25x+4x^{2}-6x+10

=10x^{3}-11x^{2}+19x+10

Co-efficient of

x^2=–11

and

x=+19

Sum

=-11+19=8

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