Answer:
See below
Explanation:
The LHS and RHS are exactly the same, so the equality is true.
The associate property of addition says that
![\boxed{a+(b+c)=(a+b)+c}](https://img.qammunity.org/2021/formulas/mathematics/high-school/w7qj7gb6y917vmpeaok57pjkgfqb7nvl6i.png)
In order to make the addition of fractions, the denominators should be same. So we can write three fractions as one.
![(1)/(2) +\left((2)/(3)+(3)/(4) \right )](https://img.qammunity.org/2021/formulas/mathematics/high-school/bci3qji5d4eq7f89xi26aot9yzqlblzb4o.png)
![(1)/(2) +(2)/(3)+(3)/(4)](https://img.qammunity.org/2021/formulas/mathematics/high-school/fdxe3ntiwfbf0e0bk8omfhg4l2fifde2yg.png)
![(1\cdot 6 )/(2\cdot 6) +(2 \cdot 4)/(3 \cdot 4)+(3 \cdot 3 )/(4 \cdot 3)](https://img.qammunity.org/2021/formulas/mathematics/high-school/sdybehr77l1r6b99rmza0p0j614ok3ie4u.png)
![( 6 )/(12) +(8)/(12)+(9 )/(12)](https://img.qammunity.org/2021/formulas/mathematics/high-school/ndmj614io78gxier0hye7zq10eyhy903rq.png)
![( 23 )/(12)](https://img.qammunity.org/2021/formulas/mathematics/high-school/ju8dp44p2pyb8z7kkenvmvsyyzixk522s5.png)