The graph of y=|2x+c| passes through the points (1,2) and (0,4) . Find the value of the constant c . Sketch the graph of y=|2x+c| .

from

|2x+c| = y
for the point (1,2)
|2+c| = 2
2+c=2 or -2-c = 2
c = 0 or c = -4

for the point (0,4)
|c| = 4
c = 4 or c = -4

the common solution is c = -4
sketch y = 2x - 4 and y = -2x + 4 and use only the part that lies above the x-axis.
the graph will be in the shape of a V with the "vertex" on the x-axis at (2,0)