y+3=2(x-1)

$${\mathtt{y}}{\mathtt{\,\small\textbf+\,}}{\mathtt{3}} = {\mathtt{2}}{\mathtt{\,\times\,}}\left({\mathtt{x}}{\mathtt{\,-\,}}{\mathtt{1}}\right)$$

$${\mathtt{y}}{\mathtt{\,\small\textbf+\,}}{\mathtt{3}} = {\mathtt{2}}{\mathtt{\,\times\,}}{\mathtt{x}}{\mathtt{\,-\,}}{\mathtt{2}}$$

$${\mathtt{y}} = {\mathtt{2}}{\mathtt{\,\times\,}}{\mathtt{x}}{\mathtt{\,-\,}}{\mathtt{2}}{\mathtt{\,-\,}}{\mathtt{3}}$$

$${\mathtt{y}} = {\mathtt{2}}{\mathtt{\,\times\,}}{\mathtt{x}}{\mathtt{\,-\,}}{\mathtt{5}}$$

If x = 20

then y = 2 * 20 - 5 = 35