數學問題(1)急!

1) [x+(2x-3)]X2 = 6x-6

2)(8y-9)+(15-2y)=6-18
6y+6=-12
6y=-18
y=-3

3) 4(5÷3m)-2m-8=0
20m-6m-24=0
14m=24
m=12/7

4) 設 x 是其餘的陶瓷小貓的金額
100=3(x+3)+4x+7
93=3x+9+4x
84=7x
x=12
So, 較便宜的陶瓷小貓=12
較貴重的陶瓷小貓=12+3=15

5) [30w+20(w+1)]/(w+(w+1))=24
50w+20=24(2w+1)
50w+20=48w+24
w=2

1)x=(2x-3)
x=3
周界=3x4=12cm
2).(8y-9)+(15-2y)=6-18
8y-2y-9+15=6-18
6y=6-18+9-15
6y=-18
y=-3
3)4(5÷3m)-2m-8=0
20/3m-2m=8
20m-6m=24
14m=24
m=24/14
m=12/7
4)設x為其餘的陶瓷小貓
100-7=4(x)+3(x+3)
93=4x+3x+9
7x=84
x=12
其餘的12元
3隻的=12+3=15元
5).30(w)+20(w+1)=24
30w+20w+20=24
50w=24-20
w=0.08公斤
6).16÷(1-1/2-1/6-1/7)
=16÷(1-21/42-7/42-6/42)
=16÷8/42
=84粒

答 (1)
正方形四邊等長 => x = 2x-3 => x =3
周界 = 4x = 4(3) = 12

答 (2)
(8y-9)+(15-2y)=6-18
8y - 2y +15 -9 = -12
6y = -12-6
y = -3

答(3)
4(5÷3m)-2m-8=0
20/3m - 2m = 8
(20 /3 - 2)m = 8
(14/3) m = 8
m = 12/7

(4)
設 x = 陶瓷小貓價錢
貴的陶瓷小貓價錢 = x+3
4x + 3(x +3) + 7 = 100
7x + 16 = 100
7x =84
陶瓷小貓價錢= x =12, 貴的陶瓷小貓價錢 = x+3 = 15
(5)
(30w + 20 (w+1)) / (w+ (w+1)) = 24
50w + 20 = 24(2w +1)
50w - 48 w= 24 - 20
2w = 4
w =2

(6)
設 x = 玻璃珠總數
16 = (1/6)x + (1/7)x + (1/2) x
16 = (1 - (7 + 6 + 21)/42) x
16 = (8/42) x
= 84