Change Per Year / Starting Point at Time = 0

Algebra 1 Goal 4

Ø  y = mx + b

slope / y – intercept/

change per year / starting point at time = 0/

change per unit

Ø  You can use the stat button on the calculator to find the equation of a line given at least two points

OR

Ø  To write the equation without a calculator to predict a value

1.  Find the slope using m=y2-y1x2-x1

2.  Find the y – intercept by plugging in m, and the x & y of 1 point into y = mx + b

3.  Write the equation plugging in the m & b into y = mx + b

4.  Plug value into x (normally time) to find y

Ø  Profit is found by subtracting how much you spent from how much you made.

Ø  Your y – intercept is where x = 0

Ø  Your x – intercept is where y = 0

Ø  Quadratics

o  When an equation has a square it is a quadratic equation and will be a parabola when graphed.

o  Maximum height is found at the vertex

1.  y =

2.  type equation in y1

3.  graph

4.  2nd

5.  Trace

6.  Maximum

7.  Get to the left side of vertex and enter

8.  Move to the right of the vertex and enter

9.  Enter

10.  Look for y value normally

o 

o 

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o  Distance traveled when ball hits the ground is when height = 0 but time ≠ 0

This is found on the x axis at the 2nd x –intercept or in the table when y = 0 or….

1.  Put equation in y =

2.  Graph

3.  2nd

4.  Trace

5.  Zero

6.  Get just above and below the point on the x axis that you looking for hitting enter after each

7.  Enter

8.  x value

Ø  When an equation has an x2 you must make it = 0 to solve. 4

Then you can factor or use the calculator to find the two x –intercepts.

Ø  Range is the y values the graph covers

Ø  Domain is the x values the graph covers

Ø  Systems of equations:

o  When a problem has two separate sentences for the same situation you must make a system of equations. Solve these using elimination, substitution, or by solving both for y graphing them on the same graph and finding the point where they intersect.

1.  y =

2.  type 1st equation into y1

3.  type 2nd equation into y2

4.  graph

5.  2nd

6.  Trace

7.  Intersection

8.  Enter, enter, enter

o  To solve a system of inequalities you must graph both inequalities. Remember to arrow left and change the line beside the y1 and y2 so that it shows the proper shading. Your solution will be the quadrant or quadrants that contain the area shaded by both equations.