问题 解答题
计算与化简
(1)计算:-24÷[1-(-3)2]+(
2
3
-
3
5
)×(-15)

(2)先化简,再求值:3x+6x2-3(
2
3
x2+x)
,其中x=-5;
(3)解方程:5(x-
2
3
)=
4
3
+(x-
2
3
)

(4)解方程:
0.5x+0.9
0.5
+
x-5
3
=
0.01+0.02x
0.03
答案

(1)-24÷[1-(-3)2]+(

2
3
-
3
5
)×(-15)

=-16÷[1-9]+(-10+9)

=-16÷[-8]-1

=2-1

=1;

(2)3x+6x2-3(

2
3
x2+x)

=3x+6x2-2x2-3x

=4x2

当x=-5时,原式=4×(-5)2=100;

(3)5(x-

2
3
)=
4
3
+(x-
2
3
)

4(x-

2
3
)=
4
3

x-

2
3
=
1
3

x=1;

(4)

0.5x+0.9
0.5
+
x-5
3
=
0.01+0.02x
0.03

原方程化为

5x+9
5
+
x-5
3
=
1+2x
3

去分母,得3(5x+9)+5(x-5)=5(1+2x),

化简,得10x=3,

解得x=

3
10

计算题
单项选择题 A3型题