Answer:

Step-by-step explanation:

Answer: y = -1
Explanation: the y axis is the vertical line, the crossing line intersects at -1.
Hope this helps!
B and C are correct, A and D are incorrect
Answer:
28
Step-by-step explanation:
40% 6th graders of 70 total = 28 6th graders
40% 6th graders + 20% 7th graders = 60%
100% - 60% = 40% 8th graders
40% are 8th graders therefore the answer is 28