[填空题]
The dietary reference intake (DRI, in grdy9:*)w gzl+ *jefo povwl7u 6ams), yt:zy/yj(t- pztrtnd41,5 b iu, of protein for a sedentary male adult of mass x kg is determined by u- dbznttit 1(4 tz5 :jyy/rp,the equation y=mx+c, where m and c are constants.
For a male adult of mass 60 kg the DRI of protein is 6969 grams, and for a male adult of mass 90 kg the DRI of protein is 91.5 grams.
1.Determine the value of m and the value of c.
2.Find the DRI of protein for a male adult of mass 70 kg. y = grams
3.Suggest a reason why the equation may not be appropriate for determining the DRI of protein for a male child of mass 40 kg.