For each value of u, determine whether it is a solution to -40 = 8(u-4).

8(u-4)=-40

8u-32= -40

8u= -40 + 32

8u= -8

u= -8/8

u= -1

Let's check

8(-1 -4)

-8-32

=-40

So yes u is -1

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)