Answer:
The correct option is;
The x-intercept represents the shirts he has to sell before making a profit
Step-by-step explanation:
The given data are;
(0, -20), (1, -10), (2, 0), (3, 10), (4, 20), (5, 30), (6, 40), (7, 50), (8, 25), (9, 40), (10, 55), (11, 70)
The data show a linear relationship because successive data point increases by the same amount of 10 for x between 0 and 7 and 15 for x between 8 and 11;
Therefore;
Slope, m of the first linear portion using points (2, 0), and, (4, 20) gives;
m = (20 - 0)/(4 - 2) = 10
The equation of the line is therefore;
y - 20 = 10·(x - 4)
y = 10·x - 40 + 20
y = 10·x - 20
The y-intercept (x = 0) is y = -20
The x-intercept (y = 0) is found as follows;
0 = 10·x - 20
20 = 10·x
10·x = 20
x = 20/10 = 2
Therefore, when x = 2 we have;
Profit = y = 10·x - 20 = 10×2 - 20 = 0
Which can be expressed as, he has to sell more than 2 shirts to make profit
Therefore, the correct option is that the x-intercept represents the shirts he has to sell before making a profit.
