1.已知y1=-x+2,y2=3x+4,当x分别取何值时,y1=y2,y1<y2,y1>y2?

问题描述:

1.已知y1=-x+2,y2=3x+4,当x分别取何值时,y1=y2,y1<y2,y1>y2?
2.若直线y=ax+7经过一次函数y=4-3x和y=2x-1的图像的交点,求a的值.

1.y1=y2 :
-x+2=3x+4 => 4x=-2 => x=-1/2
y1-1/2
y1>y2 :
-x+2>3x+4 => x x=1 y=1
带入y=ax+7 => a=-6