`\color{#a8b0b4}{⸻}\color{#91999d}{⸻}\color{#7a8286}{『}\color{#636b6f}{♡} \color{#4c5356}{E}\color{#434a4d}{m}\color{#3b4244}{p}\color{#2a3133}{t}\color{#21282a}{y}\color{#1a2123}{B}\color{#141a1c}{o} \color{#0f1516}{y} \color{#05090a}{♡}\color{#0a1011}{』}\color{#141a1c}{⸻}\color{#1a2123}{⸻}`

`1)`

`x/3+x/5+x/15=6`

`(5x+3x+x)/15=6`

`(9x)/15=6`

`9x=6*14=90`

`x=90:9`

`x=10`

`2)`

`(x-2)/3+(x+1)/5+(x-3)/15=3`

`{5(x-2)}/15+{3(x+1)}/15+{x-3}/15=3`

`{5x-10+3x+3+x-3}/15=3`

`(9x-10)/15=3`

`9x-10=3*15=45`

`9x=45+10=55`

`x=55/9`

`3)`

`2x-1+(3x-1)/2=4`

`{2(2x-1)}/2+{3x-1}/2=4`

`{4x-2+3x-1}/2=4`

`(7x-3)/2=4`

`7x-3=8`

`7x=11`

`x=11/7`

`4)`

`3(2x+1)+5=2(x+1)-1`

`6x+3+5=2x+2-1`

`6x+8=2x+1`

`6x-2x=1-8`

`4x=-7`

`x=-7/4`