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Let L1 and L2 be two lines such that L...

Let `L1 and L2` be two lines such that
`L_(2) : (x+1)/-3=(y-3)/2=(z+2)/1, L_(2) : x/1 = (y-7)/-3 = (z+7)/2`
The point of intersection of `L1 and L2` is

A

(a) `(-3, 2, 1)`

B

(b) `(2, 1, -3)`

C

(c) `(1, -3, 2)`

D

(d) (0, 0, 0)

Text Solution

AI Generated Solution

The correct Answer is:
To find the point of intersection of the two lines \( L_1 \) and \( L_2 \), we will follow these steps: ### Step 1: Write the equations of the lines in parametric form For line \( L_1 \): \[ \frac{x + 1}{-3} = \frac{y - 3}{2} = \frac{z + 2}{1} = \lambda \] From this, we can express \( x, y, z \) in terms of \( \lambda \): - \( x = -3\lambda - 1 \) - \( y = 2\lambda + 3 \) - \( z = \lambda - 2 \) For line \( L_2 \): \[ \frac{x}{1} = \frac{y - 7}{-3} = \frac{z + 7}{2} = \mu \] From this, we can express \( x, y, z \) in terms of \( \mu \): - \( x = \mu \) - \( y = -3\mu + 7 \) - \( z = 2\mu - 7 \) ### Step 2: Set the equations equal to each other Now we have: 1. \( x = -3\lambda - 1 \) and \( x = \mu \) 2. \( y = 2\lambda + 3 \) and \( y = -3\mu + 7 \) 3. \( z = \lambda - 2 \) and \( z = 2\mu - 7 \) ### Step 3: Solve the equations From the first equation: \[ -3\lambda - 1 = \mu \tag{1} \] From the second equation: \[ 2\lambda + 3 = -3\mu + 7 \tag{2} \] From the third equation: \[ \lambda - 2 = 2\mu - 7 \tag{3} \] ### Step 4: Substitute and solve for \( \lambda \) and \( \mu \) First, substitute \( \mu \) from equation (1) into equations (2) and (3). Substituting into equation (2): \[ 2\lambda + 3 = -3(-3\lambda - 1) + 7 \] \[ 2\lambda + 3 = 9\lambda + 3 + 7 \] \[ 2\lambda + 3 = 9\lambda + 10 \] \[ 2\lambda - 9\lambda = 10 - 3 \] \[ -7\lambda = 7 \implies \lambda = -1 \] Now substitute \( \lambda = -1 \) back into equation (1) to find \( \mu \): \[ \mu = -3(-1) - 1 = 3 - 1 = 2 \] ### Step 5: Find the coordinates of the intersection point Now substitute \( \lambda = -1 \) into the equations for \( L_1 \): - \( x = -3(-1) - 1 = 3 - 1 = 2 \) - \( y = 2(-1) + 3 = -2 + 3 = 1 \) - \( z = -1 - 2 = -3 \) Thus, the point of intersection is \( (2, 1, -3) \). ### Step 6: Verify with \( L_2 \) Now substitute \( \mu = 2 \) into the equations for \( L_2 \): - \( x = 2 \) - \( y = -3(2) + 7 = -6 + 7 = 1 \) - \( z = 2(2) - 7 = 4 - 7 = -3 \) Both lines give the same point of intersection. ### Conclusion The point of intersection of lines \( L_1 \) and \( L_2 \) is: \[ \boxed{(2, 1, -3)} \]
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