Answer:
C; 4
Step-by-step explanation:
Mathematically, when two lines are perpendicular, the product of their slopes equal -1
in that case, we have it that;
m1 * m2 = -1
where m1 is the slope of the first line and m2 is the slope of the second line
Hence,
m2* -1/4 = -1
-m2/4 = -1
-m2 = -4
m2 = 4
