Answer:
A.
[tex]7 {}^{3 + x} [/tex]
B. 343 • 7^x
Step-by-step explanation:
if the base of two exponential number is same we add their powers up (only when multiplying)
7^3+7^x ➡7^3+x
the expansion of 7^3 = 343 so 343•7^x is also equivalent to the given expression.
