標題:
s1 maths
發問:
1. 6[2x-3(x-1)]=2x-102. 2[3x-4)+2x]=x+103. 5[2(x-3.2)+x]=x-44. [(5x-9)÷3]-[(10-x)÷2]5. Larry is 4 times as old as Tim.After 8 years,the sum of their ages will be 56.Find the respective current ages of Larry and Tim.6. A wire of 53 cm long is cut into two parts.The longer wire is... 顯示更多 1. 6[2x-3(x-1)]=2x-10 2. 2[3x-4)+2x]=x+10 3. 5[2(x-3.2)+x]=x-4 4. [(5x-9)÷3]-[(10-x)÷2] 5. Larry is 4 times as old as Tim.After 8 years,the sum of their ages will be 56.Find the respective current ages of Larry and Tim. 6. A wire of 53 cm long is cut into two parts.The longer wire is bent to form an equilateral triangle. The shorter one is bent to form a square.If the length of each side of the square is 6cm shorter than that of the triangle,find the respective lengths of the longer and shorter wires. 要歩驟!!!!!!!!!急!!!!!!!!!!!20點!!!!!!!!!!!!!!! 更新: 15點!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
最佳解答:
1. 6[2x-3(x-1)]=2x-10 6[2x-3x+3]=2x-10 12x-18x+18=2x-10 -6x+18=2x-10 -8x=-28 x=7/2 2. 2[3x-4)+2x]=x+10 2[(3x-4)+2x]=x+10 ' ( '?? 6x-8+4x=x+10 9x=18 x=2 3. 5[2(x-3.2)+x]=x-4 5[2x-6.4+x]=x-4 10x-32+5x=x-4 14x=28 x=2 4. [(5x-9)÷3]-[(10-x)÷2] =5x/3-3-5+x/2 =10/6-8+3x/6 =13x/6-8 5.Let n years old be the ages of Tim then 4n years old be the ages of Larry 4n+n+8+8=56 5n+16=56 5n=40 n=8 ∴the ages of Tim is 8 years old then the ages of Larry is 4n=4(8)=32 years old 6.Let x cm be the length of the longer wire then[ x-(6)(4)]cm be the length of the shorter wire x+[x-(6)(4)]=53 x+x-24=53 2x=77 x=77/2 ∴ the length of the longer wire is 77/2cm then the length of the shorter wire is [ x-(6)(4)] =[(77/2) -(6)(4)] =38.5-24=14.5cm PS我都是F.1,有機會錯 2014-11-01 20:56:31 補充： 樓上的題目1步驟很怪 3. 5[2(x-3.2)+x]=x-4 5(2x-6.4+x) =x-4 5(3x-6.4)=x-4 15x-32.4=x-4 這裏運算錯誤(6.4)(5)=32 15x-36.4=x 負數調過去是正 15x-28=x 15x=x+36.4 14x=36.4 x=2.6 x應是2 2014-11-01 20:58:48 補充： 題目1,樓上誤會x是乘號 2014-11-01 21:56:34 補充： cho yi 請補充x是代數or乘 升了中學,多用括號,避免誤會 (6)(2)=12 = 6×2=12 在網上避免用x(分辨不到)(雖然我用了,題六的x是代數)
其他解答:
1. 6[2x-3(x-1)]=2x-10 6[-6(x-1) =2x-10 6(-6x-6)=2x-10 -36x-6=2x -36x-16=2x -36x=2x+16 -38x=16 x=-2 2014-11-01 20:42:13 補充： 3. 5[2(x-3.2)+x]=x-4 5(2x-6.4+x) =x-4 5(3x-6.4)=x-4 15x-32.4=x-4 15x-36.4=x 15x=x+36.4 14x=36.4 x=2.6
s1 maths
發問:
1. 6[2x-3(x-1)]=2x-102. 2[3x-4)+2x]=x+103. 5[2(x-3.2)+x]=x-44. [(5x-9)÷3]-[(10-x)÷2]5. Larry is 4 times as old as Tim.After 8 years,the sum of their ages will be 56.Find the respective current ages of Larry and Tim.6. A wire of 53 cm long is cut into two parts.The longer wire is... 顯示更多 1. 6[2x-3(x-1)]=2x-10 2. 2[3x-4)+2x]=x+10 3. 5[2(x-3.2)+x]=x-4 4. [(5x-9)÷3]-[(10-x)÷2] 5. Larry is 4 times as old as Tim.After 8 years,the sum of their ages will be 56.Find the respective current ages of Larry and Tim. 6. A wire of 53 cm long is cut into two parts.The longer wire is bent to form an equilateral triangle. The shorter one is bent to form a square.If the length of each side of the square is 6cm shorter than that of the triangle,find the respective lengths of the longer and shorter wires. 要歩驟!!!!!!!!!急!!!!!!!!!!!20點!!!!!!!!!!!!!!! 更新: 15點!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
最佳解答:
1. 6[2x-3(x-1)]=2x-10 6[2x-3x+3]=2x-10 12x-18x+18=2x-10 -6x+18=2x-10 -8x=-28 x=7/2 2. 2[3x-4)+2x]=x+10 2[(3x-4)+2x]=x+10 ' ( '?? 6x-8+4x=x+10 9x=18 x=2 3. 5[2(x-3.2)+x]=x-4 5[2x-6.4+x]=x-4 10x-32+5x=x-4 14x=28 x=2 4. [(5x-9)÷3]-[(10-x)÷2] =5x/3-3-5+x/2 =10/6-8+3x/6 =13x/6-8 5.Let n years old be the ages of Tim then 4n years old be the ages of Larry 4n+n+8+8=56 5n+16=56 5n=40 n=8 ∴the ages of Tim is 8 years old then the ages of Larry is 4n=4(8)=32 years old 6.Let x cm be the length of the longer wire then[ x-(6)(4)]cm be the length of the shorter wire x+[x-(6)(4)]=53 x+x-24=53 2x=77 x=77/2 ∴ the length of the longer wire is 77/2cm then the length of the shorter wire is [ x-(6)(4)] =[(77/2) -(6)(4)] =38.5-24=14.5cm PS我都是F.1,有機會錯 2014-11-01 20:56:31 補充： 樓上的題目1步驟很怪 3. 5[2(x-3.2)+x]=x-4 5(2x-6.4+x) =x-4 5(3x-6.4)=x-4 15x-32.4=x-4 這裏運算錯誤(6.4)(5)=32 15x-36.4=x 負數調過去是正 15x-28=x 15x=x+36.4 14x=36.4 x=2.6 x應是2 2014-11-01 20:58:48 補充： 題目1,樓上誤會x是乘號 2014-11-01 21:56:34 補充： cho yi 請補充x是代數or乘 升了中學,多用括號,避免誤會 (6)(2)=12 = 6×2=12 在網上避免用x(分辨不到)(雖然我用了,題六的x是代數)
其他解答:
1. 6[2x-3(x-1)]=2x-10 6[-6(x-1) =2x-10 6(-6x-6)=2x-10 -36x-6=2x -36x-16=2x -36x=2x+16 -38x=16 x=-2 2014-11-01 20:42:13 補充： 3. 5[2(x-3.2)+x]=x-4 5(2x-6.4+x) =x-4 5(3x-6.4)=x-4 15x-32.4=x-4 15x-36.4=x 15x=x+36.4 14x=36.4 x=2.6
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