Math Problem Statement

Find the values of and x,y and z that satisfy the vector equation: (x multplied by a column vector (-2,3-1)) + (y multplied by a column vector (2,-2,1)) + (z multplied by a column vector (1,1,-2)) = (1 multplied by a column vector (3,-2,1)) + (3 multplied by a column vector (1,-1,1)) + 4(this is not a column vector). options are: z = 3y + 1 = -x/4 - 1/2 z = y + 6 = 2x + 2 No solutions. x = -3, y = 1, z = 6

Solution

We are given the vector equation:

x(231)+y(221)+z(112)=(321)+3(111)+4x \begin{pmatrix} -2 \\ 3 \\ -1 \end{pmatrix} + y \begin{pmatrix} 2 \\ -2 \\ 1 \end{pmatrix} + z \begin{pmatrix} 1 \\ 1 \\ -2 \end{pmatrix} = \begin{pmatrix} 3 \\ -2 \\ 1 \end{pmatrix} + 3 \begin{pmatrix} 1 \\ -1 \\ 1 \end{pmatrix} + 4

Step 1: Simplify the right-hand side

The right-hand side consists of two vector terms plus a scalar value 4. First, calculate the sum of the vectors:

(321)+3(111)=(321)+(333)=(654)\begin{pmatrix} 3 \\ -2 \\ 1 \end{pmatrix} + 3 \begin{pmatrix} 1 \\ -1 \\ 1 \end{pmatrix} = \begin{pmatrix} 3 \\ -2 \\ 1 \end{pmatrix} + \begin{pmatrix} 3 \\ -3 \\ 3 \end{pmatrix} = \begin{pmatrix} 6 \\ -5 \\ 4 \end{pmatrix}

Next, we add the scalar 4 to each component of the resulting vector:

(654)+4=(1018)\begin{pmatrix} 6 \\ -5 \\ 4 \end{pmatrix} + 4 = \begin{pmatrix} 10 \\ -1 \\ 8 \end{pmatrix}

So the simplified right-hand side is:

(1018)\begin{pmatrix} 10 \\ -1 \\ 8 \end{pmatrix}

Step 2: Set up the vector equation

Now we have the equation:

x(231)+y(221)+z(112)=(1018)x \begin{pmatrix} -2 \\ 3 \\ -1 \end{pmatrix} + y \begin{pmatrix} 2 \\ -2 \\ 1 \end{pmatrix} + z \begin{pmatrix} 1 \\ 1 \\ -2 \end{pmatrix} = \begin{pmatrix} 10 \\ -1 \\ 8 \end{pmatrix}

We can now break this into three separate equations based on the components:

  1. 2x+2y+z=10-2x + 2y + z = 10
  2. 3x2y+z=13x - 2y + z = -1
  3. x+y2z=8-x + y - 2z = 8

Step 3: Solve the system of equations

We have the system:

  1. 2x+2y+z=10-2x + 2y + z = 10
  2. 3x2y+z=13x - 2y + z = -1
  3. x+y2z=8-x + y - 2z = 8

We can solve this using substitution or elimination. Let’s solve it step by step.

Step 3.1: Solve for zz from equation 1

From equation (1), solve for zz:

z = 10 + 2x - 2y \tag{4}

Step 3.2: Substitute zz into equation (2)

Substitute z=10+2x2yz = 10 + 2x - 2y into equation (2):

3x2y+(10+2x2y)=13x - 2y + (10 + 2x - 2y) = -1 Simplify:

3x2y+10+2x2y=13x - 2y + 10 + 2x - 2y = -1 5x4y+10=15x - 4y + 10 = -1 5x - 4y = -11 \tag{5}

Step 3.3: Substitute zz into equation (3)

Substitute z=10+2x2yz = 10 + 2x - 2y into equation (3):

x+y2(10+2x2y)=8-x + y - 2(10 + 2x - 2y) = 8 Simplify:

x+y204x+4y=8-x + y - 20 - 4x + 4y = 8 5x+5y=28-5x + 5y = 28 xy=285(Divide by 5)x - y = -\frac{28}{5} \quad (\text{Divide by } -5)

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Math Problem Analysis

Mathematical Concepts

Linear Algebra
Vector Equations
System of Linear Equations

Formulas

Vector addition
System of linear equations: Ax + By + Cz = D

Theorems

Linear system solving (substitution or elimination)

Suitable Grade Level

Grades 10-12