唔該各位大大help下小弟thx(要step)
no1. (0.5x+2)+(15-1.5x)=1
no2. c-5/6 +3=2- c/8
no3. Ann had $100. She used part of her money to buy 7 ceramoc cats, in which 3 of them are more expensive than the rest by $3. If she had $7 left, how much do the two types of ceramic cost?
no4. Ann had a bag of glass beads. She used half of the beads to make a necklace. She and her sister then use 1/6 and 1/7 of the original number of beads respectively tp make two bracelets. Lf there are 16 glass beads left, find the original number of glass beads.
唔該各位大大thx~
mathF.1 4題
2010-07-16 11:41 pm
回答 (2)
2010-07-17 12:23 am
✔ 最佳答案
1)(0.5x+2)+(15-1.5x)=10.5x - 1.5x + 2 + 15 = 1- x + 17 = 1x = 17 - 1x = 162)c-5/6 +3=2- c/8驚理解錯題目,補多幾個 cases.
case 1 :c - 5/6 + 3 = 2 - c/8c + 13/6 = 2 - c/8c + c/8 = 2 - 13/69c/8 = - 1/69c = - 4/3c = - 4/27case 2 :(c-5)/6 +3 = 2 - c/8(c - 5) + 18 = 12 - 3c/44(c - 5) + 72 = 48 - 3c4c - 20 + 72 = 48 - 3c7c = 48 - 72 + 207c = - 4c = - 4/7case 3 :(c - 5)/6 + 3 = (2 - c)/88(c - 5)/6 + 24 = (2 - c)8(c - 5) + 144 = 6(2 - c)8c - 40 + 144 = 12 - 6c14c = - 92c = - 46/7case 4 :c - 5/6 + 3 = (2 - c)/8c + 13/6 = (2 - c)/8c - (2-c)/8 = -13/68c/8 - (2-c)/8 = -13/6(9c - 2)/8 = -13/69c - 2 = - 52/39c = - 46/3c = - 46/27
3)Let 3 cats cost $x , then the rest 7-3 = 4 cats cost $ x-3 ,3x + 4(x-3) = 100 - 73x + 4x - 12 = 937x = 105x = 15So three of them cost $ 15 each , the rest 4 cats cost $ 15-3 = $12 each.
4)Let the original number of glass beads = x ,x/2 + x/6 + x/7 = x - 1621x + 7x + 6x = 42(x - 16)34x = 42x - 6728x = 672x = 84The original number of glass beads is 84.
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