Question

Factorise the following us in appropriate identities.

i)25a²+70ab+49b² ii)4x²-9y²​

Answer 1

Answer:

We know 49a

2

+70ab+25b

2

=(7a)

2

+2(7a)(5b)+(5b)

2

We know that x

2

+2xy+y

2

=(x+y)

Here x=7a and y=5b

Therefore, 49a

2

+70ab+25b

2

=(7a)

2

+2(7a)(5b)+(5b)

2

=(7a+5b)

2

=(7a+5b)(7a+5b)

Answer 2

Answer:

1) 25a² + 70ab + 49b²

= (5a)² + 2(5a)(7b) + (7b)²

= (5a + 7b)²

2) 4x² - 9y²

= (2x)² - (3y)²

= (2x-3y)(2x+3y)