Question

For what value of a​ is a(2x+3)=9x+15+x an identity?

Answer 1

Expand the left side, group like terms on both sides, and get

(2a)x + 3a = 10x + 15

To be true for all x, equate like terms from both sides and get

2a = 10

3a = 15

Solution: a = 5

You can test the answer.

Explanation:

Expand the left side, group like terms on both sides, and get

(2a)x + 3a = 10x + 15

To be true for all x, equate like terms from both sides and get

2a = 10

3a = 15

Solution: a = 5

You can test the answer.