Given
[tex]5^3\times5^4[/tex]To find the equivalent, apply the indices product rule
That is
[tex]a^b\times a^c=a^{b+c}[/tex]This implies
[tex]5^3\times5^4=5^{4+3}[/tex]Simplify further
[tex]5^{4+3}=5^7[/tex]Therefore, the solution is option B
[tex]5^7[/tex]