Slope: Take two points from the graph, and do y-y, over x-x.
for ex. (1,2) and (2,4) do 4-2 over 2-1. your slope is 2/1= 2
y-intercept: find the one point on the graph that is exactly on the y-axis.
for ex. (4,0)= your y-intercept is 4
Answer:

Step-by-step explanation:
When the first draw is done there are 9 red balls in a sample size of 21. So there probability of drawing a red ball will be 
When the second draw is done, there will be 12 yellow balls in a sample size of 20 since the first ball will not have been replaced into the bag. So the chance of someone drawing the second ball in the second draw is 
The probability of them happening in this order is the product of both probabilities:

The probability of an event P(n), is equal to the number of the outcomes of that event n(E), divided by the total number of outcomes, or the sample space, n(S)
so



The probability of an event = 1 - probability of the same event not to happen
so P(not need repair within the first year)=1-0.25=0.75
Answer: a) 0,25; b) 0,75