Question

$(5xy + 6y ) (7xy + 9y)$
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Answer 1

Answer:

Factories:

(i) x

2

+5xy−6y

2

(ii)4x

2

y

2

−17xy+15

(iii) 5(a+b)

2

+6(a+b)+1

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ANSWER

(i) x

2

+5xy−6y

2

=x

2

+6xy−xy−6y

2

=x(x+6y)−y(x+6y)

=(x−y)(x+6y).

(ii) 4x

2

y

2

−17xy+15

=4x

2

y

2

−12xy−5xy+15

=4xy(xy−3)−5(xy−3)

=(4xy−5)(xy−3)

(iii) 5(a+b)

2

+6(a+b)+1

=5(a+b)

2

+5(a+b)+(a+b)+1

=5(a+b)[a+b+1]+[a+b+1]

=[5(a+b)+1][a+b+1]

=(5a+5b+1)(a+b+1).

Answer 2

$\huge\underline\color{green}{Answer}$

6x^2-5xy-6y^2

6x^2-5xy-6y^2= 6x^2 -9xy+4xy -6y^2

6x^2-5xy-6y^2= 6x^2 -9xy+4xy -6y^2= 3x(2x - 3y)+ 2y(2x - 3y)

6x^2-5xy-6y^2= 6x^2 -9xy+4xy -6y^2= 3x(2x - 3y)+ 2y(2x - 3y)= (3x +2y)(2x -3y)