It is the graph of y = 6/x. You can use a graphing calculator....download wabbitemu from the google play store
30-f+8f=30
30+7f=30
Move +30 to the right side. Sign changes from +30 to -30.
30-30+7f=30-30
7f=0
Divde by 7
7f/7=0/7
Cross out 7 and 7, divide by 7. Becomes 1*1*f=f
f=0
Answer: f=0