Chapter Summary
and Review
9
Chapter
VOCABULARY
• square root, p. 499
• quadratic equation, p. 505
• positive square root, p. 499
• negative square root, p. 499
• simplest form of a
radical expression, p. 511
• radicand, p. 499
• quadratic function, p. 520
• discriminant, p. 540
• perfect square, p. 500
• parabola, p. 520
• quadratic inequalities, p. 547
• radical expression, p. 501
• vertex, p. 521
• graph of a quadratic
inequality, p. 547
• roots of a quadratic
equation, p. 527
• quadratic formula, p. 533
• axis of symmetry, p. 521
9.1
Examples on
pp. 499–501
SQUARE ROOTS
EXAMPLES
Positive real numbers have a positive square root and a negative square root.
The radical symbol indicates the positive square root of a positive number.
a. 3
6 6
36 is a perfect square: 62 36.
b. 8
1 9
81 is a perfect square: 92 81, so 8
1
9 and 8
1
9.
Evaluate the expression.
1. 4
9.2
2. 1
44
3. 1
00
4. 2
5
SOLVING Q UADRATIC EQUATIONS BY FINDING SQUARE ROOTS
Examples on
pp. 505–507
To find the real solutions of a quadratic equation in the form ax2 c 0,
isolate x2 on one side of the equation. Then find the square root(s) of each side.
EXAMPLE
2x2 98 0
Write original equation.
2x 98
2
Add 98 to each side.
x2 49
Divide each side by 2.
x 49
Find square roots.
x 7
72 49 and (7)2 49
Solve the equation.
5. x2 144
6. 8y2 968
7. 5y2 80 0
8. 3x2 4 8
Chapter Summary and Review
553