Question

已知y1等于6-x,y2等于2+7x。当x取何值时，y1比y2小-3

Answer 1

y1=6-x, y2=2+7x，要使y1比y2小-3则6-x+3=2+7x解得x=7/8

Answer 2

Y1-Y2=3,Y1=6-X.Y2=2+7X.解得X=1/8,Y1=47/8,Y2=23/8

Answer 3

y1=6-x, y2=2+7x , y1=y2-3
6-x=2+7x+3 => 8x=1 => x= 1/8

Answer 4

X=7/8