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 -6 -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