Answer:
26
Step-by-step explanation:
solving the left side of the = sign with 26 put in:
8.3 x 10⁴ = 83000
-26 x 10³ = -26000
83000 - 26000 = 57000
solving the right:
5.7 x 10⁴ = 57000
with 26 put in front of the -, both sides become equal, making it true.
