Answer:
y = x + 1
Step-by-step explanation:
1) First, find the slope of the line between the two points. Whichever option has the same slope would be the right answer. To find this, use the slope formula
.
and
represent the x and y values of one point, and
and
represent the x and y values of another point.
So, use the points given to answer the question. Substitute 4 for
, 5 for
, 8 for
, and 9 for
then solve:

Therefore, the slope is 1.
2) Any line that is in a "y = a number" format is a horizontal line, and all horizontal lines have a slope of 0 - so the second option can't be the answer.
The rest of the options are in slope-intercept form, or y = mx + b format. Remember that the coefficient of the term with the x is the slope. Knowing this, y = x + 1 would need to be the answer since the coefficient of the term with the x is 1, and we already calculated that the slope is 1.