解二次 Solve Quadratic (S4)
Instructions to use S4 for solving quadratic equations
Output symbols 
1st output: R1 - First root
2nd output: R2 - Second root
3rd output: Y - y-coordinate of the vertex
4th output: X - corresponding x of Y, axis of symmetry
5th output: S1 - The number before the radical sign in the surd
6th output: S2 - The number inside the radical sign in the surd
Finding the roots of a quadratic equation  
For ax² + bx + c = 0 where A, B and C are constants,
Input a into [A?]
Input b into [B?]
Input c into [M?]
Output R1 and R2 are the roots of the equation
The roots are not real if [R<=>I] is shown on the top right corner
For x =
 -b ± √(b² - 4ac) 
/2a
 ,
Output S1 and S2 helps present the solution in surd form
x = S1 ± √S2
Finding the vertex of the graph 
The vertex of the graph is (X, Y)
Completing the square 
ax² + bx + c = a (x - X) + Y where a = 1
Factorization 
In ax² + bx + c where a = 1,
Let   m  / n  be R1 and   y  / z  be R2

ax² + bx + c  = (x - R1) (x- R2)
  = (x -   m  / n ) (x -   y  / )
  = (nx - m) (zx - y)//


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