Question

Can someone please explain to me how to solve this problem? I have the answer already all I need is to know how to solve the problem.

Answer 1

Answer:

Step-by-step explanation:

you have two supplementary angles,

both added up=180

7y+5y=12y

12y=180y=15

angle DBC=7y=15*7=105

Answer 2

Answer:

Step-by-step explanation:

You know that angle DBA = 180 degrees.

Therefore you can write an equation:

7y+5y=180

12y=180

y=15

Now, you know that y = 15, you can multiply 7 * 15 = 105 degrees