![\begin{gathered} A)-18-3=-15\Rightarrow false(mistake) \\ B)x=-126 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/mmei3957j709lv2gnsr52qcj5k3pum070a.png)
Step-by-step explanation
![\begin{gathered} (x)/(6)+3=-18 \\ \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/udnnqfnyoa4ba291ue30mty5boxh8tlh91.png)
Step 1
to find the solution we need to isolate x, so
a)subtract 3 in both sides
so
![\begin{gathered} (x)/(6)+3=-18 \\ subtract\text{ 3 in both sides} \\ (x)/(6)+3-3=-18-3 \\ (x)/(6)=-21 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/kdhz1qiobz1hhczhb2ccopj5ehr5npvnwo.png)
therefore, the mistake the student did is
he did :
![-18-3=-21\Rightarrow False](https://img.qammunity.org/2023/formulas/mathematics/college/sgdtcu7xmybsfs5t9vqyyi7xa6r4cjna38.png)
Step 2
now, to find the true value for x , let's continue with the solution
![\begin{gathered} (x)/(6)=-21 \\ \text{Multiply both sides by 6} \\ (x)/(6)\cdot6=-21\cdot6 \\ x=-126 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/cqhp88xx24jussvvfpgqv1lanffx10mbf3.png)
therefore, the answer is
![x=-126](https://img.qammunity.org/2023/formulas/mathematics/college/xpim879lz6rguluwpamrw7a64365tovngt.png)
I hope this helps you