Answer:
[tex]a=7[/tex]
Step-by-step explanation:
[tex]Given\ the\ expression\ of\ perimeter=7a-2\\\\Perimeter=47\\\\\Rightarrow 7a-2=47\\\\add\ 2\ both\ sides\\\\7a-2+2=47+2\\\\7a+0=49\\\\7a=49\\\\Divide\ both\ sides\ by\ 7\\\\\frac{7a}{7}=\frac{49}{7}\\\\a=\frac{7\times 7}{7}\\\\a=7[/tex]
