Question

Which is the equation of the graph ?

Answer 1

I think first option is that right answer

Answer 2

Answer: Hello there!

In your graph you can see two things, first, your function only has negative values (and decreasing, so it never is positive), and second, it intersects the x-axis in x = 3.

The first thing says to us that we should discard the second and third options, because they allow positive values for y (you can evaluate them in x = 10 for example, and see that y is positive).

Now we get the first and fourth options to analyze:

1) $y = -\frac{1}{2} Ix-3I$

2) $y = -\frac{1}{2} IxI - 3$

if you evaluate this functions in x = 3, y should be 0.

in the first equation this is trivial, and in the second you got:

y = 3/2 - 3 = -3/2

so this equation didn't give us 0.

Then the correct answer is the first option.