Can anyone help solve this equation?

Answer:
13
Step-by-step explanation:
3 x 3 = 9
7 + 3 = 10
7 + ? = 3 + 7 + 3 + 7
7 + ? = 20
? = 13
Answer:
Step-by-step explanation:
[tex]p\times p=9\\\\p^2=9\to p=\sqrt9\to \boxed{p=3}\\\\c+p=10\qquad\text{put the value of}\ p\\\\c+3=10\qquad\text{subtract 3 from both sides}\\\\\boxed{c=7}\\\\c+s=p+c+p+c\qquad\text{put the values of}\ p\ \text{and}\ c\\\\7+s=3+7+3+7\\\\7+s=20\qquad\text{subtract 7 from both sides}\\\\\boxed{s=13}[/tex]