Respuesta :

The sum of angles of a triangle equals the straight angle (180°), therefore:

3x + 12x + 1 + 16x - 7 = 180

31x-6=180

31x = 180 + 6

31x = 186

x = 186/31

x = 6

Answer: It's 31x + -6

Step-by-step explanation:

Add all the numbers with x together because they all have the same variable

Then add the -7 to 1 to get -6 since they both don't have variables and are the same

Lastly just put the equation together and there you go!:)

Hope you see the sun now