Question

Use distributive law to factor the given expression: 3+21a+15b

Answer 1

`3(1+7a+5b)`

Explanation:

The distributive law states that

`a\cdot (b+c)=a\cdot b+a\cdot c.`

The expression 3+21a+15b consists of three terms:

1. 3=3·1;
2. 21a=3·7a;
3. 15b=3·5b.

You can see that 3 is the common factor of these three terms, thus

`3+21a+15b=3(1+7a+5b).`