Answer Key 219

11. xy

()xy+

=

()()

()

2

(^22) y
2
2 2
+(−
92 −(−
= ()
9 −()(−
2
2 2

−
49
81 4
=^49
77

7
11

12. (y + z)−3 = ((−2)+(−3))−3
    = (−2 − 3)−3
    = (−5)−3

=^13

()− 5

=

1

− 125

=−

1

125

13. Abbhh= ⋅⋅

1

2

1

2

1284 = 8

14. Vrrhh= ()()()=

1

3

1

3

(^2) h ())(( 471
1
π )(

15. c^2 = a^2 + b^2
    c^2 = 8^2 + 15^2
    c^2 = 64 + 225
    c^2 = 289
    c is 17 or −17


16. −− +

⎛

⎝⎜

⎛⎛

⎝⎝

⎞

⎠⎟

⎞⎞

⎠⎠=−

1

2

73 − 0

1

2

32 3330 ⎞⎞⎞ 73 + 0

(^123)
xy^3 xy xy^37 xy

17. (8a^3 + 64 b^3 ) = 8 a^3 + 64 b^3


18. −4 − (−2y^3 ) = −4 + 2 y^3


19. −3(x + 4) = −3x − 12


20. 12 + (x^2 + y) = 12 + x^2 + y