题目内容

填空:
(1)已知
x
2
=
y
3
=
z
4
≠0,则
2x+y-z
3x-2y+z
=______.
(2)若分式
3x2-12
x2+4x+4
的值为0,则x的值为______.
(3)已知
a
x+2
b
x-2
的和等于
4x
x2-4
,则a=______,b=______.
(4)已知x为整数,且
2
x+3
+
2
3-x
+
2x+18
x2-9
为整数,则所有符合条件的x值的和为______.
(1)设
x
2
=
y
3
=
z
4
=t,则x=2t,y=3t,z=4t,则
2x+y-z
3x-2y+z
=
4t+3t-4t
6t-6t+4t
=
3t
4t
=
3
4

故答案是:
3
4


(2)
3x2-12=0
x2+4x+4≠0

解得:x=2,
故答案是:2.;

(3)
a
x+2
+
b
x-2
=
a(x-2)+b(x+2)
(x+2)(x-2)
=
(a+b)x-2a+2b
x2-4

a+b=4
-2a+2b=0

解得:a=b=2.
故答案是:2,2;

(4)
2
x+3
+
2
3-x
+
2x+18
x2-9
=
2(x-3)
(x+3)(x-3)
-
2(x+3)
(x+3)(x-3)
+
2x+18
(x+3)(x-3)

=
2(x-3)-2(x+3)+2x+18
(x+3)(x-3)

=
2x+6
(x+3)(x-3)

=
2
x-3

根据题意得:x-3=±1或±2.
解得:x=4或2或5或1.
则4+2+5+1=12.
故答案是:12.
练习册系列答案
相关题目

违法和不良信息举报电话:027-86699610 举报邮箱:58377363@163.com

精英家教网