QuestionJuly 16, 2025

Write the equation for the plane. The plane through the points P(5,4,-36),Q(-3,6,-16) and R(-1,-5,42) A. 4x+6y+z=8 B. 4x+6y+z=-8 C. 6x+y+4z=-8 D. 6x+y+4z=8

Write the equation for the plane. The plane through the points P(5,4,-36),Q(-3,6,-16) and R(-1,-5,42) A. 4x+6y+z=8 B. 4x+6y+z=-8 C. 6x+y+4z=-8 D. 6x+y+4z=8
Write the equation for the plane.
The plane through the points P(5,4,-36),Q(-3,6,-16) and R(-1,-5,42)
A. 4x+6y+z=8
B. 4x+6y+z=-8
C. 6x+y+4z=-8
D. 6x+y+4z=8

Solution
4.2(201 votes)

Answer

None of the given options match the correct equation. Explanation 1. Find two vectors in the plane Calculate \overrightarrow{PQ} = Q - P = (-3-5, 6-4, -16+36) = (-8, 2, 20) and \overrightarrow{PR} = R - P = (-1-5, -5-4, 42+36) = (-6, -9, 78). 2. Calculate the normal vector using cross product Compute \overrightarrow{PQ} \times \overrightarrow{PR}: ((-8)(-9) - (2)(78), (20)(-6) - (-8)(78), (-8)(-9) - (2)(-6)) = (72 - 156, -120 + 624, 72 + 12) = (-84, 504, 84). 3. Simplify the normal vector Simplify to (1, -6, 1) by dividing each component by 84. 4. Write the equation of the plane Use point P(5,4,-36) and normal vector (1, -6, 1): 1(x - 5) - 6(y - 4) + 1(z + 36) = 0. Simplify: x - 5 - 6y + 24 + z + 36 = 0 \Rightarrow x - 6y + z + 55 = 0. Rearrange: x - 6y + z = -55.

Explanation

1. Find two vectors in the plane<br /> Calculate $\overrightarrow{PQ} = Q - P = (-3-5, 6-4, -16+36) = (-8, 2, 20)$ and $\overrightarrow{PR} = R - P = (-1-5, -5-4, 42+36) = (-6, -9, 78)$.<br />2. Calculate the normal vector using cross product<br /> Compute $\overrightarrow{PQ} \times \overrightarrow{PR}$: <br /> $((-8)(-9) - (2)(78), (20)(-6) - (-8)(78), (-8)(-9) - (2)(-6)) = (72 - 156, -120 + 624, 72 + 12) = (-84, 504, 84)$.<br />3. Simplify the normal vector<br /> Simplify to $(1, -6, 1)$ by dividing each component by 84.<br />4. Write the equation of the plane<br /> Use point $P(5,4,-36)$ and normal vector $(1, -6, 1)$: $1(x - 5) - 6(y - 4) + 1(z + 36) = 0$.<br /> Simplify: $x - 5 - 6y + 24 + z + 36 = 0 \Rightarrow x - 6y + z + 55 = 0$.<br /> Rearrange: $x - 6y + z = -55$.
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