Question

Factorise the following.
(i) 4a2 + 20a +25
Tiini
22​

Answer 1

Answer:

(2a+5)(2a+5)

Step-by-step explanation:

i) 4a²+20a+25

= (2a)²+2(2a)(5)+(5)²

[using identity (a+b)²= a²+2ab+b²]

= (2a+5)²

= (2a+5)(2a+5)

Hope It Helps

Answer 2

Answer:

Rewrite

4

a

2

as

(

2

a

)

2

.

(

2

a

)

2

+

20

a

+

25

Rewrite

25

as

5

2

.

(

2

a

)

2

+

20

a

+

5

2

Check that the middle term is two times the product of the numbers being squared in the first term and third term.

20

a

=

2

⋅

(

2

a

)

⋅

5

Rewrite the polynomial.

(

2

a

)

2

+

2

⋅

(

2

a

)

⋅

5

+

5

2

Factor using the perfect square trinomial rule

a

2

+

2

a

b

+

b

2

=

(

a

+

b

)

2

, where

a

=

2

a

and

b

=

5

.

(

2

a

+

5

)

2