1. Calculator Shortcut – Solving Trinomials

2. x2 + 5x + 4 = 0 Solving Trinomials Example 1: Solve for x:
We can solve for x when there’s an equal sign
When x is squared, there will be two numbers that work for this equation

3. x2 + 5x + 4 = 0 Solving Trinomials Example 1: Solve for x:
There are different things they will ask for:
Solve
Find the roots
Find the solutions
Find the zeros

4. x2 + 5x + 4 = 0 Solving Trinomials
To solve this we can factor it, or we can use our calculators!
Let’s see how to use our calculators to solve any trinomial!

5. Solving Trinomials
Go to y=
Enter the equation into Y1
Enter 0 in Y2

6. Solving Trinomials
Press GRAPH
You should see the graph on your screen

7. Solving Trinomials Press 2nd CALC Go to 5: INTERSECT and press enter
You should be back at the graph

8. Solving Trinomials
Move your cursor to where the equation crosses the x-axis on the right side
Press ENTER
Keep the cursor where it is and press ENTER again

9. Solving Trinomials It should now be asking you to Guess
Press ENTER one more time
The X value is one of your two answers!

10. Solving Trinomials
We have to follow the same steps to find the other answer
Press 2nd CALC
Go to 5: INTERSECT and press enter
You should be back at the graph

11. Solving Trinomials
Move your cursor to where the equation crosses the x-axis on the left side
Press ENTER
Keep the cursor where it is and press ENTER again

12. Solving Trinomials It should now be asking you to Guess
Press ENTER one more time
The X value is your second answer

13. x2 + 5x + 4 = 0 Solving Trinomials Example 1: Solve for x:
The answer to this are the two x-values you found: -1 and -4

14. Solving Trinomials This technique works anytime there’s an x2 value!
Always make sure all the numbers are on one side of the equals sign and zero is on the other!

15. x2 + x = 6 -6 -6 x2 + x – 6 = 0 Solving Trinomials
Example 2: Find the roots of
x2 + x = 6
You have to get all the numbers on one side of the equals, so subtract 6 from both sides
x2 + x – 6 = 0

16. x2 + x – 6 = 0 Solving Trinomials
Now plug the equation into y1 and zero for y2
x2 + x – 6 = 0

17. -2x2 + x – 5 = 0 Solving Trinomials Example 3: Find the solutions to
When you graph this you should see:
If it doesn’t cross the x- axis then there’s no solution