I've done downloading dependency manually (gcc) but it wont start the installation

My printer is HP InkAdventages 2020 Hc, I've done downloaded manually the dependency (gcc).

I'm using hplip-3.19.1 on my elementary os (base on Ubuntu 18.04)

INSTALL MISSING REQUIRED DEPENDENCIES
-------------------------------------
note: Installation of dependencies requires an active internet connection.
warning: Missing REQUIRED dependency: gcc (gcc - GNU Project C and C++ Compiler)
warning: This installer cannot install 'gcc' for your distro/OS and/or version.
error: Installation cannot continue without this dependency. Please manually install this dependency and re-run this installer.

That is the error that I got. But GCC has been installed on my laptop.

root@ekta**:/home/ria***/Downloads# apt install gcc
Reading package lists... Done
Building dependency tree
Reading state information... Done
gcc is already the newest version (4:7.3.0-3ubuntu2.1).
The following packages were automatically installed and are no longer required:
  gir1.2-vte-2.91 libb64-0d libevent-2.1-6 libido3-0.1-0 libllvm6.0 libminiupnpc10 libnatpmp1
  linux-headers-4.15.0-36 linux-headers-4.15.0-36-generic linux-image-4.15.0-36-generic
  linux-modules-4.15.0-36-generic linux-modules-extra-4.15.0-36-generic
Use 'sudo apt autoremove' to remove them.
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.

What's wrong on my installation? Thank you!