Answer :

[tex](4p - 7)^{\frac{1}{2}} = 5[/tex]
[tex] \sqrt{4p-7} = 5 [/tex]
[tex]( \sqrt{4p-7} )^{2} = 5^{2}[/tex]
[tex]4p - 7 = 25[/tex]
[tex]4p = 25 + 7 \\ 4p = 32 \\ p = 32/4 \\ p = 8[/tex]

Hope this helps! :)