a).解方程8x+7=13(x-1)
b.由a小題的結果，解方程8/y+7=13(8/y+7=13(1/y-1)
thz
急~f1既maths題(15分)
2008-03-09 9:41 pm
回答 (5)
2008-03-09 11:23 pm
✔ 最佳答案
a)8x+7 = 13 ( x-1 )
8x+7 = 13x-13
7+13 = 13x-8x
20 = 5x
20/5 = x
4 = x〃
b)
8/y+7 = 13 [ 8/y+7+13 ( 1/y-1) ]
8/y+7 = 13 [ 8/y+7+13/y-13 ]
8/y+7 = 104/y+91+169/y-169
8/y+7 = 273/y-78
-71 = 265/y
-71y = 256
y = 256/-71
y = -3⊿52⊿71
y = -3.732394366...〃
2008-03-09 10:52 pm
a).解方程8x+7=13(x-1)
8x+7=13(x-1)
8x+7=13x-13
7+13=13x-8x
20=5x
5x=20
x=4
b. 8/y+7=13(8/y+7+13(1/y-1)
8/y++7=138/y+7+13/y-13)
8/y+7=104/y+91+169/y-169
8/y+7y/y=104/y+91y/y+169/y-169y/y
8+7y=104+91y169-169y
-7y-91y+169y=104+169-8
85y=265
y=85/265=17/53
8x+7=13(x-1)
8x+7=13x-13
7+13=13x-8x
20=5x
5x=20
x=4
b. 8/y+7=13(8/y+7+13(1/y-1)
8/y++7=138/y+7+13/y-13)
8/y+7=104/y+91+169/y-169
8/y+7y/y=104/y+91y/y+169/y-169y/y
8+7y=104+91y169-169y
-7y-91y+169y=104+169-8
85y=265
y=85/265=17/53
參考: me
2008-03-09 9:53 pm
a)8x+7=13(x-1)
8x+7=13x-13
20=5x
x=4
p.s.唔知你b題打咩,,有2個等於??
8x+7=13x-13
20=5x
x=4
p.s.唔知你b題打咩,,有2個等於??
2008-03-09 9:52 pm
a).
8x+7=13(x+1)
8x+7=13x+13
8x=13x+13-7
8x=13x+6
8x-13x=6
-5x=6
x=-1.2
b).Let 1/y=x
8x+7=13(x)
7=13x-8x
5x=7
x=1.4
1/y=1.4
1.4y=1
y=0.714285714285......(5/7)
8x+7=13(x+1)
8x+7=13x+13
8x=13x+13-7
8x=13x+6
8x-13x=6
-5x=6
x=-1.2
b).Let 1/y=x
8x+7=13(x)
7=13x-8x
5x=7
x=1.4
1/y=1.4
1.4y=1
y=0.714285714285......(5/7)
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