Let us revise the rules of exponents
[tex]a^n\times a^m=a^{n+m}[/tex][tex](a^n)^m=a^{nm}[/tex]
We will use these 2 rules to solve the question
[tex](x^{22})(x^7)^3=(x^{22})(x^{7\times3})[/tex]
Multiply 7 by 3, then add to the answer 22
[tex](x^{22})(x^{21})=x^{22+21}=x^{43}[/tex]
Now equate it by x^p
[tex]x^p=x^{43}[/tex]
Then p = 43
