 # Calculator Shortcut – Solving Trinomials

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Calculator Shortcut – Solving Trinomials

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

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

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!

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

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

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

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

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

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

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

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

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

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!

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

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

-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