Question 255156
4).  y=|-3x| 
40). y=-|x-3| 

Remember the definition of absolute value:

|a| = a if a>=0
|a| = -a if a<0

So for #4 above we have y = -3x when -3x >= 0 and y = -(-3x) = 3x when -3x < 0.  Dividing both sides of these inequalities by -3 and reversing the sign of the inequalities (because we are dividing by a negative) we have -3x >= 0 if and only if x < 0. Similarly -3x < 0 if and only if x>=0.

So we have:

the line y = -3x when x <= 0 and
the line y = 3x when  x > 0

These are two "half" iines which form a "V" with the low point at (0,0) and opening upward around the y-axis.

#40 is very similar. The "V" is shifted to the right to the point (3,0) and opens downward.

I hope this helps.