We can apply some logic before touching formulas or anything.
See my attachment.
We are told that the slope is positive. We are also told that the x-intercept (where y=0) of the line is 3 i.e. x=3, y=0 (3,0). Therefore we can broadly plot this line enough to rule out a few answers:
We are asked for the y-intercept i.e. where x=0, what is the y-coordinate the line intercepts?
We can rule out (C), (D) and (E) based on our diagram.
Now solve for the y-intercept knowing it needs to be a negative value by plotting in the information we have
General form of line: y=mx +b
m (gradient) = 3
y=
3x +b
we can determine b from the x-intercept
when x=3, y=0
0=3(3)+B
b=-9
y=
3x -
9Y-intercept is where x=0
Y= 3(0) -9
Y= -9
Attachments
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