help with DAX lookup syntax

hi,

i have 2 unrelated tables in an SSAS tabular mode:

Location Values:

AcctId, LocationValue,  Date

1          1,000,000           6-30-2017

1          500,000              6-30-2017

1          300,000              6-30-2017

Premium Values:

AcctId, PremiumValue, Date

1           100,000            6-30-2017

I want to bring the sum of the LocationValues into the PremiumValues table by joining on the AcctId and Date fields.

So in the Above example, i should end up with this in the PremiumValues table:

Premium Values:

AcctId, PremiumValue, Date,           LocationValue

1           100,000            6-30-2017  1,800,000

I think LookupValue will work, but not sure of the syntax.  I tried of couple of ways, but it keeps failing.

Scott