10. Two perpendicular lines

$$\begin{array}{lcl} The\;line\;y=mx+b\;in\;the\;xy-coordinate\;plane\;is\;\\ perpendicular\;to\;the\;line\;2y+x=8\;and\;both\;lines\;\\ passes\;through\;the\;point\;(2,2).\\ What\;is\;the\;value\;of\;b?\\ \\ (F)\; -2\\ (G)\; 1\\ (H)\; 2\\ (J)\; -1\\ (K)\; 4\\ \end{array}$$