(1)计算:-25÷(-4)×(12)2-12×(-15+24)3(2)先化简,再求值:12x-2(x-13y2)+(-32x+13y2)

2025-05-21 05:29:35
推荐回答(1个)
回答(1):

(1)原式=-32×(-

1
4
×
1
4
)-12×1=2-12=-10;
(2)原式=
1
2
x-2x+
2
3
y2-
3
2
x+
1
3
y2=-3x+y2
当x=-2,y=-
2
3
时,原式=(-3)×(-2)+(-
2
3
2=6+
4
9
=
58
9

(3)去分母得:3(3y+1)=24-4(2y-1),
去括号得:9y+3=24-8y+4,
移项得:9y+8y=24+4-3,
合并得:17y=25,
解得:y=
25
17