Practice B
Cjrd^& Qnblo*s
For use with Pages 671-676
cAV
your solutions to
use the quadratic formula to solve the equation. Round
the nearest hundredth, if necessary'
3x2-x-16:0
l. x2+7x-80:0
3. 8x2-2x-30:0
s. -x2+x*12:0
7. sxz + 30x * 32: 0
9. 4x2-x-20:0
8 x2+4x*1:o
@ -3x2-4x*10:0
x2+6x-1oo:o
I
5x2+x-9:0
@ l0x2-7x*5:0
11. 6x2+7x-3:0
Tell which method(s) you woutd use to solve the quadratic equation'
Explain your choice(s).
14.
13. 6x2 - 216: A
16. x2+8x*7:0
$a2
=
56
17. x2-6x*1:0
15.
la-
5x2
- llx:0
:
-9x2 + 10x
5
solve the quadratic equation using any method. Round your solutions
to the nearest hundredth, if ne-cessary.
@ -rorz - -50
:,t4x - 4e
@ xz
@
6
x2
x2
-
r6x: -.64
+ 6x: t4
fd
6
x2
+ 3x- 8:
-5xz +
x:
t3
y
715,. Pasta For the period 1990-2003, the amount of biscuits, pasta, and noodles
by
be
modeled
can
States
United
the
into
(in thousands of metric tons) imported
1990.
years
since
of
the
number
is
y 136* 27.8x + 304 where x
the firnction
:
*
the year in which
and solve an equation that you can use to approximate
,eys1s
imported.
500 million pounds of biscuits, pasta, and noodles
Write and solve dn equation that you can use to approximate the year in which
575 million pounds olbiscuits, pasta, and noodles were imported.
a. Write
b.
26.
Eggs For the period lggT-2}O3,the number of eggs y (in billions) produced in
: -.0.27x2 * 3.3x f 77 yhere
the United States can be modeled by the functiony
:]'#H-TJ1'JJ:f:-J;l',li;r""
Algebra
:
=i
=
o'
E
o
=
o
-o
C
'6
'=
E
o
E
=o
o
=
ooO
Graph the function on a graphing calculator. Use the trace featute to fi:rd the year
when 80 billion eggs were prbduced. Use the graph to check your answer from
-o
billion eggs were Produced.
part (a).
72
>
C
sa
o
=l
(.)
can use to approximate the vear(s) in which
80
b.
o
1
Chapter 10 Hesource Book
>
(slJ
E
o
'=
>
a
o
(-)
Name
Practice B
For use with pages 677-683
Tell whether the equation has frnro solutions, one solution, ot no solution-
1. x2+x*3:0
4. 3x2 - 9x * 8 :0
7. 36xz - 9x: 0
@ ** *3:x
2.
5.
8.
@
3. -Zx2+10x-5:0
6. -4x2+g:0
- 4x - 5:0
L0x2-8x*1:0
3x2 + 2: 4x
2x2
-8x2
@
o
- g*:?
12:
8x2
x2
-
6x
+ !2x * 2:
4x
Find the number of x-intercepts that the graph of the function has,
rD v:x2-6x-3
6 y:x2*x*,
19.
!:2x2-4x*2
22.
,=
x-l
@!:5x2@Y:-4x2*x*1
io. y:lOxz-5;r*1
23.
y:i,*'-4x*8
@!:6x2-6x-tl
18' !:4x2*5x-l
21- !:8x2*x*4
- !:?*' 5x*2
"15x2+3x*5
Give a value of c for which the equation has (a) two solutions,
(b) one solution, and (cl nb solutionu
25. x2 + l}x * c:0
2a.
31.
49x2
- 74x*c:.0
* c:0
29. 2x2 + 4x*c:0
26.
x2
-
4x
27.25x2+ 10x*c:0
30.
Playhouse You want to build a playhouse for your sister in your,
baclryard. You have blueprints which show that the playhouse is
72 feetlong and 13 feet wide. You want to change the dimensions
as shown. The new area can be modeled by the function
y:-x2fx*156.
Write in equhtion that you can use to determine if there is a
value ofx that gives aD,atea of 150 square feet'
Use the discriminant of your equation from part (a) to show
that it is possible to find a value of x for which the area is
a.
b.
3xz
.t
-
78x
* c:0
>
E
12ft__] xl -r
-'r
13ft
I
150 square feet.
c.
Find the value(s) of x for which the area is 150 square feet.
g2.
Tennis You and your friend are walking around the exterior of a tennis court that
has a 12-foot high fence around it. You pick up a ball and try to throw it from a
, height of 5 feet over the fence. You throw it with an initial vertical velocity of 20 feet
per second. Did the ball make it over the fence?
:t
rl
its-x
rl
llrl
-. -L
'= oao
C.)
.C
'o=
=
rt
.=o
-o
.C
,a
'=
o
6
=o
o
=
ooo
t
@
E
o
'=
>
a
Uo
{
E
Algebra
82
1
Chapter 10 Resource Book
: