MS Word

1. Name:___________________________________________________Grade & Section:_______________
SOLVING QUADRATIC EQUATIONS
Casio FX 991 MS Calculator
Instruction:
*Press Mode when you want to solve equation.
EQN ………….……………………………
*Entering EQN Mode and pressing displays the initial quadratic equation screen
*Press 2 for quadratic equation and input values for each of the coefficient.
*You can use the and keys to move between coefficients on the screen and make changes,
if you want.
*Pressing the key returns to the coefficient input screen.
Example: To solve the equation
푥2 − 7푥 + 10 = 0 (푥 = 5, 2 )
(Degree?) 2
(푎? ) 1
(푏? ) 7
(푐? ) 10
(푥1 = 5)
(푥2 = 2)
Find the roots of the following equations.
1.) 3푥2 − 10푥 − 8 = 0 푥 = ____________
2.) 3푥2 + 13푥 − 10 = 0 푥 = ____________
3.) 푥2 + 2푥 − 15 = 0 푥 = ____________
4.) 푢2 − 4푢 − 12 = 0 푢 = ____________
5.) 6푥2 − 푥 − 12 = 0 푥 = ____________
6.) 2푦2 − 7푦 + 13 = 0 푦 = ____________
7.) 3푎2 − 6 = 17푎 푎 = ____________
8.) −20푥 − 3 = 25푥2 푥 = ____________
9.) 2푥2 + 푥 = 6 푥 = ____________
10.) 36푎2 + 9푎 = 10 푥 = ____________
Prepared By: Caryl Mae S. Puertollano

2. ANSWER KEY
Find the roots of the following equations.
1.) 3푥2 − 10푥 − 8 = 0 푥 = −
2
3
, 4
2.) 3푥2 + 13푥 − 10 = 0 푥 =
2
3
, -5
3.) 푥2 + 2푥 − 15 = 0 푥 = -5 , 3
4.) 푢2 − 4푢 − 12 = 0 푢 = 6, -2
5.) 6푥2 − 푥 − 12 = 0 푥 = −
4
3
,
3
2
6.) 2푦2 − 7푦 + 3 = 0 푦 =
1
2
, 3
7.) 3푎2 − 6 = 17푎 푎 = −
1
3
, 6
8.) −20푥 − 3 = 25푥2 푥 = −
3
5
, −
1
5
9.) 2푥2 + 푥 = 6 푥 =
3
2
, -2
10.) 36푎2 + 9푎 = 10 푎 = −
2
3
,
5
12