Quadratic Equations Practice Questions

 polynomialsQuadratic Equations Practice Questions

Solving Quadratic questions appear on most College exams and some High School Proficiency exams

1. Find 2 numbers that sum to 21 and the sum of the squares is 261.

a. 14 and 7
b. 15 and 6
c. 16 and 5
d. 17 and 4

2. Using the factoring method, solve the quadratic

equation: x2 + 4x + 4 = 0
a. 0 and 1
b. 1 and 2
c. 2
d. -2

3. Using the quadratic formula, solve the quadratic
equation: x – 31/x = 0
a. -?13 and ?13
b. -?31 and ?31
c. -?31 and 2?31
d. -?3 and ?3

4. Using the factoring method, solve the quadratic
equation: 2x2 – 3x = 0
a. 0 and 1.5
b. 1.5 and 2
c. 2 and 2.5
d. 0 and 2

5. Using the quadratic formula, solve the quadratic
equation: x2 – 9x + 14 = 0
a. 2 and 7
b. -2 and 7
c. -7 and -2
d. -7 and 2

 

Answer Key

1. B
The numbers are 15 and 6.
x + 7 = 21 => x = 21 -7
x2 + y2 = 261
(21 – 7 )2 + y2 = 261
441 – 42y + y2 + y2 = 261
2y2 – 42y + 180 = 0

y2 – 21y + 90 = 0
y1,2 = 21 + ?441 – 360/2
y1,2 = 21 + ?81/2
y1,2 = 21 + 9/2
y1 = 15
y2 = 6
x1 = 21 = y1 = 21 – 15 = 6
x2 = 21 – y2 = 21 – 6 = 15

2. D

-2

15

 

 

 

 

 

 

 

3. B

21

 

 

 

 

 

 

 

4. A

0 and 1.5
2x2 – 3x = 0
x(2x – 3)
x = 0 or 2x – 3 =0
x = 0 or x = 3/2
x = 0 or x = 1.5

5. A
2 and 7

20

Written by:
Modified: September 14th, 2017

Published: April 6th, 2014

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