计算与化简(1)计算:?24÷[1?(?3)2]+(23?35)×(?15);(2)先化简,再求值:3x+6x2?3(23x2+x),其中x=-

2025-04-08 09:42:59
推荐回答(1个)
回答1:

(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