a m p ; L = x + 1 3 = y + 3 5 = z + 5 7 a m p ; P Q = x − 15 7 1 = y − 32 7 4 = z − 7 7 = λ \begin{aligned}& L=\frac{x+1}{3}=\frac{y+3}{5}=\frac{z+5}{7} \\& P Q=\frac{x-\frac{15}{7}}{1}=\frac{y-\frac{32}{7}}{4}=\frac{z-7}{7}=\lambda\end{aligned} am p ; L = 3 x + 1 = 5 y + 3 = 7 z + 5 am p ; PQ = 1 x − 7 15 = 4 y − 7 32 = 7 z − 7 = λ
a m p ; ⇒ Q ( λ + 15 7 , 4 λ + 32 7 , 7 λ + 7 ) a m p ; Since Q lies on line L a m p ; a m p ; So, λ + 15 7 + 1 3 = 7 λ + 7 + 5 7 a m p ; ⇒ 7 λ + 22 = 21 λ + 36 a m p ; ⇒ λ = − 1 a m p ; ∴ Point Q ( 8 7 , 4 7 , 0 ) a m p ; P Q = ( 15 7 − 8 7 ) 2 + ( 32 7 − 4 7 ) 2 + ( 7 − 0 ) a m p ; P Q = 66 a m p ; ⇒ ( P Q ) 2 = 66 \begin{aligned}&\Rightarrow \mathrm{Q}\left(\lambda+\frac{15}{7}, 4 \lambda+\frac{32}{7}, 7 \lambda+7\right)\\&\text { Since } \mathrm{Q} \text { lies on line } \mathrm{L}\\&\begin{aligned}& \text { So, } \frac{\lambda+\frac{15}{7}+1}{3}=\frac{7 \lambda+7+5}{7} \\& \Rightarrow 7 \lambda+22=21 \lambda+36 \\& \Rightarrow \lambda=-1 \\& \therefore \text { Point } Q\left(\frac{8}{7}, \frac{4}{7}, 0\right) \\& \mathrm{PQ}=\sqrt{\left(\frac{15}{7}-\frac{8}{7}\right)^2+\left(\frac{32}{7}-\frac{4}{7}\right)^2+(7-0)} \\& \mathrm{PQ}=\sqrt{66} \\& \Rightarrow(\mathrm{PQ})^2=66\end{aligned}\end{aligned} am p ; ⇒ Q ( λ + 7 15 , 4 λ + 7 32 , 7 λ + 7 ) am p ; Since Q lies on line L am p ; am p ; So, 3 λ + 7 15 + 1 = 7 7 λ + 7 + 5 am p ; ⇒ 7 λ + 22 = 21 λ + 36 am p ; ⇒ λ = − 1 am p ; ∴ Point Q ( 7 8 , 7 4 , 0 ) am p ; PQ = ( 7 15 − 7 8 ) 2 + ( 7 32 − 7 4 ) 2 + ( 7 − 0 ) am p ; PQ = 66 am p ; ⇒ ( PQ ) 2 = 66