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

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.

Step-by-step 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.

d. bc = 12 and ef = 16

step-by-step explanation:

we are given that δabc : δdef such that .

also, it is given that

so, from the options, we need that .

a.

b.

c.  

d.

as, we can see that only option d gives the same ratio as i.e. .

hence, the possible lengths are bc = 12 and ef = 16.