STAAR A1 TI-84 Calculator Lesson

STAAR A1 TI-84 Calculator Lesson

TI-84 Calculator tricks to drastically improve your grade on the STAAR Algebra 1 EOC

EQUAL GRAPHS

Which of these two expressions are equivalent?

EQUAL GRAPHS

Highlighted in red are all the buttons you will use.

Highlighted in blue are the menus you will be working in.

Example 1

The most obvious version of this question will ask you directly whether some expression is equivalent to some other expression.

Open "y=" and input the original expression into "Y1"

Go down to "Y2" and input one of the other expressions.

Example 1

Once you have 2 expressions in your "y=" to compare, just press "graph" and take a look.

If the expressions are equivalent, then the graphs will be identical.

In this case, we can tell that the red and blue graphs are slightly different, and are therefore NOT EQUIVALENT.

Example 1

Since the original expression, $2x^2+7x+4$ , has a different graph than answer choice (F),  $\left(2x+1\right)\left(x-4\right)$ , we can eliminate (F) and continue to test the other answer choices using the same method.

Example 2

This question is worded differently, but can be answered using the same method.

Example 3

This question is worded differently, but can be answered using the same method.

Area equals length (5x+4) times width (4x-4).

 $A=\left(5x+4\right)\left(4x-4\right)$ 

GRAPH AND CHECK

The problem only gives you one equation/expression and you don't know what to do with it?

GRAPH AND CHECK

Highlighted in red are all the buttons you will use.

Highlighted in blue are the menus you will be working in.

Example 4

This problem gives us the formula for a certain type of equation, and then tells us that 2 of the variables in that formula "are both less than 0."

"are both less than 0" is just another way of saying "are both negatives"

Example 4

Since it only tells us that these numbers need to be negative, we can choose any negative numbers to test this problem.

I will be using "a=-2" and "b=-3"

Therefore,  $y=-2x^2-3$ 

Example 4

Compare each answer choice to your graph and select the closest one.

In this case, (H) is the closest match and is therefore the correct answer.

Example 5

This question is worded differently, but can be answered similarly.

Go to "y=" and input both f(x) and g(x), then compare their graphs and choose the best answer.

GRAPH AND CALCULATE

You have one or more equations, and the question is asking you about a specific math vocabulary term?

ex: value, zero, intersect, solution, rate of change, y-intercept, etc.

GRAPH AND CALCULATE

Highlighted in red are all the buttons you will use.

Highlighted in blue are the menus you will be working in.

Example 6: Value

Open "y=" and input the given function.

Open "graph" and make sure the graph is visible. (If not, "Zoom" then "0" will resize the graph to fit.)

Example 6: Value

Press "2nd" then "trace" to open the "CALCULATE" menu

Press "1" for "value" and you will be sent back to the graph screen.

Type in the given value and press enter to find the answer.

Example 7: Zero

Another word for "zero" is "x-intercept."

If a function's highest exponent is a "2," then a zero may be called a "solution" instead. (in other words, for all quadratic functions)

Example 7: Zero

Open "y=" and input the given function.

Open "graph" and make sure the graph is visible.

Open the "CALCULATE" menu.

Press "2" for "zero" to be sent back to the graph.

Example 7: Zero

"Left Bound?" will be present at the bottom of the screen.

Make sure the cursor is on the graph to the left of the "zero" you want to find, then press enter.

"Right Bound?" works the same way, but move the cursor to the right side instead.

Example 7: Zero

Once you have entered your left and right bounds, press "enter" one last time to find the answer.

It will show up as "x=?" in the bottom-left corner of the screen.

CALCULATE: intersect

• The "solution" to a system of linear equations is where the 2 lines intersect.

• The "solution" to a single equation can be found the same way. Input the left and right sides of any equation as separate equations and find their intersection. (When solved this way, your "solution" is the x-value.)

Example 8: Intersect

This problem asks for the solution to a single inequality.

Open "y=" and input the left and right sides of the inequality as separate equations.

Example 8: Intersect

Open "graph" and make sure the intersection is visible.

Open the "CALCULATE" menu.

Press "5" for "intersect" to be sent back to the graph.

Example 8: Intersect

You should see "First curve?" on the bottom of the screen.

Press "enter" 3 times and the intersection will display at the bottom of the screen.

Since our original problem had only one variable, then we only need the x-value for this problem.

TABLE AND CHECK

Does the question give you a table AND an equation?

TABLE AND CHECK

Highlighted in red are all the buttons you will use.

Highlighted in blue are the menus you will be working in.

Example 9

All we need to do is see which one of those functions produces this table!

Open "y=" and input the equation.

Example 9

Press "2nd" and then "graph" to open the "table"

If the table on your calculator matches the table in the problem, then that's your answer!

The x-value of 0 produces a "1" in our calculator, but in the problem we can see that an x-value of 0 SHOULD give us 0.0625 instead.

Example 9

Since the table in our calculator didn't match the table in the problem, we can mark out (F) and test the other answer choices using the same method.

This method will solve ANY problem that gives you at least 1 equation and 1 table.

STAT AND (ax+b)

The problem gives you at least 2 points, like (x, y), and asks you for the slope, rate of change, or y-intercept?

STAT AND (ax+b)

Highlighted in red are all the buttons you will use.

Highlighted in blue are the menus you will be working in.

Buttons with a red line through them are buttons you frequently use on other problems, but NOT ON THESE.

Example 10

If a problem gives you at least 2 points, (in a table, on a graph, or in the text) then we can use the "stat" feature on our calculator to solve for the slope (aka rate of change) and y-intercept (aka starting value).

Press the "stat" button and then "enter" to open the tables screen.

Example 10

Choose 2 or more points from the original problem.

Input the x-values under "L1"

Input the y-values under "L2"

Make sure the coordinates from the problem are next to each other!

Now press "stat" and then "right" to open the "CALC" menu. Then press "4" for "LinReg(ax+b).

Example 10

Press "enter" 5 times on the LinReg(ax+b) screen to produce the answer.

a = m = slope = rate of change

b = y-intercept = starting value

-4.5 is the same as  $-\frac{9}{2}$ , so the answer for example 10 is (B)

This method can be used on ANY problem that gives you at least 2 points and asks about the slope, rate of change, y-intercept, starting value, or equation in slope-intercept form.