Pearson Algebra 1 Common Core, 2011
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Pearson Algebra 1 Common Core, 2011 View details
4. Graphing a Function Rule
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Exercise 29 Page 258

Substitute some arbitrary values for x to find their corresponding y-values.

Practice makes perfect

One way to graph a function rule is by making a table of values and substituting some arbitrary values for x. Doing so will give the corresponding values of y, which we can use to form ( x, y) coordinate pairs.

x -2x^2 y (x,y)
-2 -2( -2)^2 -8 ( -2, -8)
-1 -2( -1)^2 -2 ( -1, -2)
0 -2( 0)^2 0 ( 0, 0)
1 -2( 1)^2 -2 ( 1, -2)
2 -2( 2)^2 -8 ( 2, -8)
Let's plot these points on a coordinate plane.

By connecting all of our points with a line, we form the graph of the function rule. Because there is a variable with an exponent in the function, our line will not be straight. Later, we will learn that this type of function is called a cuadratic function and this type of graph is called a parabola.