已知y1=6-x,y2=2+7x,当x取何值时,y1比y2小-3

已知y1=6-x,y2=2+7x,当x取何值时,y1比y2小-3

已枯高尘知y1=6-x,y2=2 7x. (1)当x取何值时,y1=2y2? (2)当x取何值念迅时(1)y1=2y2:6-x=2*(2 7x) 15x=2 x=2/没禅15 (2)y1比y2小-3 6-x
1. y1=6-x, y2=2+7x , y1=y2-3
6-x=2+7x-3 => 8x=7 => x= 7/8
即:y2-y1=-3
2+7x-6+x=-3
8x=1
x=1/8
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