Question

(a) Factorise completely


$5a {}^{2} - 20$
​

Answer 1

Step-by-step explanation:

5a²-20

5(a²-4)..,..,

Answer 2

Step-by-step explanation:

Given :-

5a²-20

To find:-

Factorise 5a²-20

Solution:-

Given expression is 5a²-20

=>(5×a²)-(5×4)

=>5(a²-4)

=>5(a²-2²)

=>5(a+2)(a-2)

since a²-b²=(a+b)(a-b)

Answer:-

5a²-20=5(a+2)(a-2)

Used formula:-

• (a+b)(a-b)=a²-b²