Ever since Ubuntu upgraded to 16.04 with php 7 setting up LAMP server is not very difficult but getting it up is sometimes troublesome. specially running php7 because running php7 on apache also need to install mbstring and libapache2-mod-php you can use following commands on terminal to install these packages and within in no moment you will have your php working.
sudo apt install php libapache2-mod-phpsudo apt install php7.0-mbstring
