Answer:
[tex]f(x) = 8 x + 5...(1) \\ f(x) = 21...(2) \\ (1) = (2) \\ 8x + 5 = 21 \\ 8x = 21 - 5 \\ 8x = 16 \\ x = \frac{16}{8} = 2 \\ x = 2 \\ thank \: you[/tex]
[tex]f(x) = 8x + 5 \\ f(x) = 21 \\ 8x + 5 = 21 \\ 8x = 21 - 5 \\ 8x = 16 \\ x =\frac{16}{8} \\ \boxed{x = 2}[/tex]
