Answer:
k=3
Step-by-step explanation:
3(7k-1)= 4k+6
1. you do distributive property of 3(7k-1) and you get 21k-3, which is 21k-3=4k+6.
2. you +3 to both sides and get: 21k=7k+9
then you divide 7k on both sides: 3k=9
3. then divide 3 to both sides to get your answer: k= 3
B
5050
S=n*(n+1) / 2
S=100 * (100+1) /2 = 50 * 101 = 5050
