Answer:
a=3
Step-by-step explanation:
Three or more lines in a plane are said to be concurrent if they intersect at a single point.
First find the point of intersection of lines y=x+4 and 2y+x=2. Substitute y=x+4 into the second equation:
2(x+4)+x=2
2x+8+x=2
2x+x=2-8
3x=-6
x=-2
Then
y=-2+4=2
So, the point of intersection is (-2,2). The coordinates of this point must satisfy the equation of the third line, thus
2=a·(-2)+8
2=-2a+8
2a=8-2
2a=6
a=3
