Answer:
![\boxed{ \bold{ \huge{ \boxed{ \sf{x = 0.875}}}}}](https://img.qammunity.org/2021/formulas/mathematics/high-school/lo0lmro5bo5858ce5itfgfoqd44b85wfon.png)
Explanation:
![\sf{3[ x + 3(4x - 5)] = 15x - 24}](https://img.qammunity.org/2021/formulas/mathematics/high-school/371vx0jyvddbntyrdn96w0n6h1gjft36k9.png)
Distribute 3 through the parentheses
⇒
![\sf{3[ x + 12x - 15 ] = 15x - 24}](https://img.qammunity.org/2021/formulas/mathematics/high-school/20cth70sc4s3krogo0z6z7ng9tkwq7o7k7.png)
Collect like terms : 12x and x
⇒
![\sf{3[ 13x - 15 ] = 15x - 24}](https://img.qammunity.org/2021/formulas/mathematics/high-school/9ucutgttqttf5bvu1gccbeeoxz32s1hy5t.png)
Distribute 3 through the parentheses
⇒
![\sf{39x - 45 = 15x - 24}](https://img.qammunity.org/2021/formulas/mathematics/high-school/c0uh987j3xgb8x8knjyukfn9vbie2weklh.png)
Move 15x to left hand side and change it's sign
Similarly, move 45 to right hand side and change it's sign
⇒
![\sf{39x - 15x = - 24 + 45}](https://img.qammunity.org/2021/formulas/mathematics/high-school/k5tiam7pq88lvarixuyshqhsvokdoc8b1s.png)
Collect like terms
⇒
![\sf{24x = - 24 + 45}](https://img.qammunity.org/2021/formulas/mathematics/high-school/fkucdfeclzctioelk4rhlk7qppls7ex2nl.png)
Calculate
⇒
![\sf{24x = 21}](https://img.qammunity.org/2021/formulas/mathematics/high-school/7vd56rd73qnadi55dcg1370axyk33irhc0.png)
Divide both sides of the equation by 24
⇒
![\sf{ (24x)/(24) = (21)/(24)}](https://img.qammunity.org/2021/formulas/mathematics/high-school/d134mak1wbo2y8s2nqi08if80fu3siphzk.png)
Calculate
⇒
![\sf{x = 0.875}](https://img.qammunity.org/2021/formulas/mathematics/high-school/inqhgzyjxv8630clstsrzd8emndigc0k8c.png)
Hope I helped!
Best regards! :D