Please solve the following differential equations $/$ initial value problems:

a$)$ y$\text{'}\text{'}($x$)-2$y$\text{'}($x$)+$ y$($x$)=1$

b$)$ y$\text{'}($x$)+2$y$($x$)=$ x

c$)$ y$\text{'}\text{'}($x$)=1,$ y$\text{'}(1)=1,$ y$(1)=1$