20-1=19 hop this helps :)
Answer:
The answer is 10/143
Step-by-step explanation:
Answer:
x=-2 y=-6
Step-by-step explanation
5x+4=-3x-12
+3 +3x
8x+4=-12
-4 -4
8x=-16
÷8 ÷8
x=-2
Looking for y too, plug x into the original equation
5(-2)+4
-10+4
-6
y=-6
True since the dot product is defined as a.b=abcos(x)
since they are perpendicular x=90 cos(90)=0
hence a.b=0