`x xx 4/15 = 6/7`
`x=6/7 : 4/15`
`x=6/7 xx15/4`
`x=(6xx15)/(7xx4)`
`x=45/14`
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`x : 4/9 =7/4`
`x=7/4 xx 4/9`
`x= (7xx4)/(4xx9)`
`x=7/9`
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`x-7/15=6/5`
`x=6/5+7/15`
`x=18/15+7/15`
`x=25/15`
`x=5/3`
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`15/19 : x =8/5 -4/15`
`15/19:x=24/15-4/15`
`15/19:x=4/3`
`x=15/19:4/3`
`x=15/19xx3/4`
`x=45/76`
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`15/4 -x =5/12+4/3`
`15/4-x=5/12+16/12`
`15/4-x=21/12`
`15/4-x=7/4`
`x=15/4-7/4`
`x=8/4`
`x=2`
\(b,x=\dfrac{6}{7}:\dfrac{4}{15}\\ x=\dfrac{6}{7}\times\dfrac{15}{4}\\ x=\dfrac{45}{14}\)
\(c,x=\dfrac{7}{4}\times\dfrac{4}{9}\\ x=\dfrac{7}{9}\)
\(d,x=\dfrac{6}{5}+\dfrac{7}{15}\\ x=\dfrac{18}{15}+\dfrac{7}{15}\\ x=\dfrac{25}{15}\\ x=\dfrac{5}{3}\)
\(g,\dfrac{15}{19}:x=\dfrac{24}{15}-\dfrac{4}{15}\\ \dfrac{15}{19}:x=\dfrac{20}{15}\\ \dfrac{15}{19}:x=\dfrac{4}{3}\\ x=\dfrac{15}{19}:\dfrac{3}{4}\\ x=\dfrac{15}{19}\times\dfrac{4}{3}\\ x=\dfrac{20}{19}\)
\(h,\dfrac{15}{4}-x=\dfrac{5}{12}+\dfrac{16}{12}\\ \dfrac{15}{4}-x=\dfrac{21}{12}\\ \dfrac{15}{4}-x=\dfrac{7}{4}\\ x=\dfrac{15}{4}-\dfrac{7}{4}\\ x=\dfrac{8}{4}\\ x=2\)
