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Tìm các số nguyên x, y biết :
\(\eqalign{ & a){3 \over x} = {y \over {35}} = {{ – 6} \over {14}} \cr & b){x \over 4} = {{ – 15} \over {12}} = {{x + y} \over {16}} \cr & c){x \over 2} = {3 \over y}. \cr} \)
\(\eqalign{ & a){3 \over x} = {y \over {35}} = {{ – 6} \over {14}} \cr & {3 \over x} = {{ – 6} \over {14}} \Rightarrow 3.14 = x.( – 6) \cr&\Rightarrow x = {{3.14} \over { – 6}} = {{42} \over { – 6}} = – 7 \cr & {y \over {35}} = {{ – 6} \over {14}} \Rightarrow y.14 = 35.( – 6)\cr& \Rightarrow y = {{35.( – 6)} \over {14}} = {{ – 210} \over {14}} = – 15 \cr & b){x \over 4} = {{ – 15} \over {12}} = {{x + y} \over {16}} \cr & {x \over 4} = {{ – 15} \over {12}}\cr& \Rightarrow x.12 = 4.( – 15) \cr&\Rightarrow x = {{4.( – 15)} \over {12}} = {{ – 60} \over {12}} = – 5 \cr & {{ – 5} \over 4} = {{ – 5 + y} \over {16}} \cr&\Rightarrow – 5.16 = 4.( – 5 + y) \cr&\Rightarrow – 5 + y = {{ – 5.16} \over 4} = {{ – 80} \over 4} = – 20 \cr&\Rightarrow y = – 20 + 5 = – 15. \cr} \)
\(\eqalign{
& c)\,\,\,\frac{x}{2} = \frac{3}{y} \Rightarrow x.y = 2.3 \cr
& \,\,\,\,\,\,\, \Rightarrow x.y = 6 \cr} \)
\( \Rightarrow x,y\) là ước số của 6
|
x |
1 |
-1 |
2 |
-2 |
3 |
-3 Advertisements (Quảng cáo) |
6 |
-6 |
|
y |
6 |
-6 |
3 |
-3 |
2 |
-2 |
1 |
-1 |