Let the number of history textbooks be h and the number of physics textbooks be p.
It was given that the bookstore sells a combined total of 347 books. Thus we have:
[tex]h+p=347[/tex]It is also given that the number of history textbooks sold was 79 more than the number of physics textbooks. This gives:
[tex]h=p+79[/tex]We can substitute for h into the first equation:
[tex]p+79+p=347[/tex]Solving, we have:
[tex]\begin{gathered} 2p+79=347 \\ 2p=347-79 \\ 2p=268 \\ p=\frac{268}{2} \\ p=134 \end{gathered}[/tex]Substitute for p in the second equation, we have:
[tex]\begin{gathered} h=p+79 \\ h=134+79 \\ h=213 \end{gathered}[/tex]Therefore, there were 134 physics textbooks and 213 history textbooks.