Which equation has both 7 and -7 as a
possible value of x?

Where are the equations?? Provide them so we can choose which one of them has both 7 and -7 as a possible value of x

δabc ≅ δdcb by sas because

db ≅ ac . . given (side)

bc ≅ bc . . reflexive property (side)

∠dbc ≅ ∠ acb . . alternate interior angles where transversal bc crosses parallel lines bd and ac (included angle)