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If the line, $$\frac{x - 3}{1} = \frac{y + 2}{-1} = \frac{z + \lambda}{-2}$$ lies in the plane, $$2x - 4y + 3z = 2$$, then the shortest distance between this line and the line, $$\frac{x - 1}{12} = \frac{y}{9} = \frac{z}{4}$$ is
Let the given line be represented in the symmetric form
$$\frac{x-3}{1}=\frac{y+2}{-1}=\frac{z+\lambda}{-2}=t$$
so that every point on it is
$$x=3+t,\;y=-2-t,\;z=-\lambda-2t\;.-(1)$$
This line is known to lie entirely in the plane
$$2x-4y+3z=2\;.-(2)$$
Substituting the coordinates from $$-(1)$$ into the plane equation $$-(2)$$ gives
$$2(3+t)-4(-2-t)+3(-\lambda-2t)=2.$$
Simplifying term by term, first expand each bracket:
$$6+2t+8+4t-3\lambda-6t=2.$$
Combine like terms for $$t$$:
$$6+8+(2t+4t-6t)-3\lambda=2,$$
$$14+0t-3\lambda=2,$$
$$14-3\lambda=2.$$
Rearrange to isolate $$\lambda$$:
$$-3\lambda=2-14=-12,$$
$$\lambda=4.$$
Thus the first line is finally
$$\frac{x-3}{1}=\frac{y+2}{-1}=\frac{z+4}{-2}.$$
Its direction vector is therefore
$$\mathbf{d}_1=\langle1,-1,-2\rangle.$$(3)
For the second line we write
$$\frac{x-1}{12}=\frac{y}{9}=\frac{z}{4}=s,$$
yielding the parametric coordinates
$$x=1+12s,\;y=9s,\;z=4s\;.-(4)$$
The direction vector of this line is
$$\mathbf{d}_2=\langle12,9,4\rangle.$$(5)
To compute the shortest distance between two possibly skew lines, we employ
$$\text{Distance}=\frac{\lvert(\mathbf{a}_2-\mathbf{a}_1)\cdot(\mathbf{d}_1\times\mathbf{d}_2)\rvert}{\lvert\mathbf{d}_1\times\mathbf{d}_2\rvert},$$
where $$\mathbf{a}_1$$ and $$\mathbf{a}_2$$ are any chosen points on the first and second lines respectively.
Choose the convenient points obtained at $$t=0$$ in $$-(1)$$ and $$s=0$$ in $$-(4):$$
$$\mathbf{a}_1=(3,-2,-4),\quad\mathbf{a}_2=(1,0,0).$$(6)
The joining vector is
$$\mathbf{a}_2-\mathbf{a}_1=\langle1-3,\;0-(-2),\;0-(-4)\rangle=\langle-2,2,4\rangle.$$(7)
Compute the cross product of the direction vectors.
$$\mathbf{d}_1\times\mathbf{d}_2= \begin{vmatrix} \mathbf{i}&\mathbf{j}&\mathbf{k}\\[4pt] 1&-1&-2\\[4pt] 12&9&4 \end{vmatrix}.$$
Expanding the determinant:
$$\mathbf{d}_1\times\mathbf{d}_2= \mathbf{i}\bigl((-1)\cdot4-(-2)\cdot9\bigr) -\mathbf{j}\bigl(1\cdot4-(-2)\cdot12\bigr) +\mathbf{k}\bigl(1\cdot9-(-1)\cdot12\bigr).$$
Compute each component:
$$\mathbf{i}( -4+18)=14\mathbf{i},$$
$$-\mathbf{j}( 4+24)=-28\mathbf{j},$$
$$\mathbf{k}(9+12)=21\mathbf{k}.$$
Thus
$$\mathbf{d}_1\times\mathbf{d}_2=\langle14,-28,21\rangle.$$(8)
The magnitude of this vector is
$$\lvert\mathbf{d}_1\times\mathbf{d}_2\rvert =\sqrt{14^{2}+(-28)^{2}+21^{2}} =\sqrt{196+784+441} =\sqrt{1421}.$$(9)
Now evaluate the scalar triple product in the numerator:
$$(\mathbf{a}_2-\mathbf{a}_1)\cdot(\mathbf{d}_1\times\mathbf{d}_2) =\langle-2,2,4\rangle\cdot\langle14,-28,21\rangle.$$
Take the dot product term by term:
$$(-2)(14)+(2)(-28)+(4)(21)=-28-56+84=0.$$(10)
Because the numerator equals zero, the entire fraction vanishes:
$$\text{Distance}= \frac{\lvert0\rvert}{\sqrt{1421}}=0.$$(11)
Therefore the two lines intersect, and the least separation is zero.
Hence, the correct answer is Option D.
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