IN/OUT TABLE, SLOPE, and Y-INTERCEPT PRACTICE
The variables (x and y) in the equation of a line have a relationship between each other. As the value
of one variable changes, so does the value of the other variable.
In the equation y = 4x – 1


When x = 3, y is equal to 4(3) – 1 = 12 – 1 = 11.
If x is equal to 4, then y is equal to 4(4) – 1 = 16 – 1 = 15.
Remember:
4x means “4 times x,”
so 4(0) means “4 times 0.”
Thus 4(0) = 0 and 4(2) = 8
For any equation of a line, we can make an input/output table to show the relationship between x and y.
The input/output table of y = 4x – 1 shows the value of y for different values of x:
The middle column of the table shows the substitution of a number for x, and the last column shows the
value of y after those calculations have been performed. Most input/output tables do not show the
middle column, just the values of x and y.
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(1)
On a separate sheet of paper, make In/Out Tables for the following equations. Each table
should include x and y values (at least three of each), properly labeled. It is up to you if you want to
include a column that includes the equation.
Example (this is what should be on your paper):
y = 2x + 1
x
0
1
2
2(0) + 1 =
2(1) + 1 =
2(2) + 1 =
This type of table is also OK:
y = 2x +1
x
0
1
2
y
1
3
5
y
1
3
5
(2)
For each equation, near each table, write the slope and y-intercept.
Example (same equation as above): y = 2x + 1
Slope (m) = 2
Y-Intercept (b) = 1
 Remember, SLOPE or “m” is the number “before the x” (this is called the coefficient).


It does NOT include the x, but it DOES include a negative sign if there is one.
Example:
y = -3x + 1, the slope is -3
If there is no number before the x (no coefficient), then the SLOPE = 1.
Example:
y = x + 999, the slope is 1
 The Y-INTERCEPT or “b” (if the equation is written in y = mx + b form) is the number at the end
(it never has an x or y attached to it).


It DOES include the negative sign if there is one.
Example:
y = 4x – 5 (this is the same as y = 4x + -5), so the y-intercept is -5
If there is no number at the end, the y-intercept is 0.
Example:
y = 12x, the y-intercept is 0
Equations for practice:
1. y = 5x + 2
2. y = 2 x – 3
3. y = x
4. y = -2x + 4
5. y = -x – 1
6. y = 3x + 0
7. y = -8x
8. y = 4x – 5
9. y = 10x
10. y = x – 6
Worth 40 points:
20 (2 per equation) for tables
10 (1 per equation) for slope
10 (1 per equation) for y-intercept