Well, (3,1,1) are the direction ratios! And if this line passes through (4,5,5), substitue it in the general equation,
\frac{x-x_1}{a}=\frac{y-y_1}{b}=\frac{z-z_1}{c}
where, (a,b,c) are the direction ratios and (x_1,y_1,z_1) is the point through which the line passes!