A group of related facts that use the same number is a fact family
Answer:The answer is B
Step-by-step explanation: because mitchells line is traveling steeper than matthews
C. 6 pens for $6.42
Divide to find the number for one pen. then multiply
Use elimination
-x - y = -9
x - y = 3
Add both equations
-2y = -6, y = 3
-x -(3) = -9
-x = -6, x = 6
Final answer: x = 6, y = 3