Answer:
7.04 x 10⁵.
Step-by-step explanation:
Remember that when adding or subtracting numbers in scientific notation, the exponents must be the same.
In this case, we can adjust 5.40 x 10⁴ to 0.540 x 10⁵ and add it to 6.50 x 10⁵ and we obtain:
You can see that we just sum the bases, ie 6.50 and 0.540, and we put the same exponent of 10. So, the answer would be 7.04 x 10⁵.