Question

Hallar "a" si: a4a en base 7 =120a en base 5.

Answer 1

$a4a_{7} = 120a_{5} \\ 7^{2} .a+7.4+a=5^{3}.1 + 5^{2}.2 +a \\ 49a+28+a=125+50+a \\ 50a+28=175+a \\ 49a=147 \\ a=3$