Final answer:
To perform the operation 1.26x10^4 + 2.50x10^4, add the coefficients to get 3.76 and keep the exponent of 10 the same, resulting in a sum of 3.76x10^4 expressed in scientific notation.
Step-by-step explanation:
To add the numbers 1.26x104 and 2.50x104 and express the answer in scientific notation, we must first acknowledge that both numbers already have the same exponent of 10. Thus, we only need to add the coefficients (1.26 and 2.50) and retain the common exponent.
The sum of the coefficients is 1.26 + 2.50 = 3.76. Therefore, the sum in scientific notation is 3.76x104.