How to solve this equation 6x-1= - 7

∠1 and ∠2 are complementary. ∠1=x°∠2=(3x+30)° select from the drop down menu to correctly answer the question. what is the value of x? . a.15 b.25 c.30 d.40 e.55

Anyone know? will mark brainliest if correct

The variable in a relation who’s value depends on the value of the independent variable is called what?