∑ Old Books, New Math

Chapter 23 · Quadratic Equations

Chapter challenge

Ten problems drawn from every lesson in the chapter. Get each one right on your first try for a perfect score. A new set is drawn each time.

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From Quadratic Equations with Literal Coefficients, exercise 3

Solve for x by completing the square, and check:

1

x^2 + 2ax + a^2 - 4 = 0

From Problems Leading to Quadratics, exercise 2

Reject all answers which do not satisfy the conditions of the problems. Where two answers both satisfy a problem, give both.

2

Find two numbers whose difference is 11 and whose product is 42.

From Solution by Formula, exercise 4

Solve for x by formula, and check:

3

2x + 2 = x^2

From Solution by Completing the Square, exercise 20

Solve by completing the square, and check results:

4

25x^2 - 20x - 12 = 0

From Solution by Completing the Square, exercise 18

Solve by completing the square, and check results:

5

20s^2 + s = 1

From Geometrical Problems, exercise 7

Use the figures in the lesson.

6

In the figure of the two chords, AC = 18, DB = 4, and BE = 20. Find AB.

From Solution by Completing the Square, exercise 7

Solve by completing the square, and check results:

7

t^2 - 2t - 15 = 0

From Problems of Rate, Work, and Falling Bodies, exercise 27

Reject all answers which do not satisfy the conditions of the problems.

8

Two pumps together can fill a standpipe in 45 minutes. One pump alone requires 2 hours less time than the other. Find the time each requires alone.

From Quadratic Equations with Literal Coefficients, exercise 11

Solve for x by completing the square, and check:

9

a^2x^2 + 2ab = a^2 + b^2

From Harder Equations; Equations in the Quadratic Form, exercise 44

Solve these equations in the quadratic form (each has four roots):

10

4k^4 = 9k^2 - 2