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If 3[xyzw]=[x612w]+[4x+yz+w3]3\begin{bmatrix} x & y \\ z & w \end{bmatrix} = \begin{bmatrix} x & 6 \\ -1 & 2w \end{bmatrix} + \begin{bmatrix} 4 & x + y \\ z + w & 3 \end{bmatrix}, then the values of x,y,zx, y, z and ww are

Solution

Correct Option: 3

The equation is:

3[xyzw]\begin{bmatrix} x & y \\ z & w \end{bmatrix} = [x612w]\begin{bmatrix} x & 6 \\ -1 & 2w \end{bmatrix} + [4x+yz+w3]\begin{bmatrix} 4 & x+y \\ z+w & 3 \end{bmatrix}


When multiplying a matrix by 3, multiply each element by 3:

3[xyzw]\begin{bmatrix} x & y \\ z & w \end{bmatrix} = [3x3y3z3w]\begin{bmatrix} 3x & 3y \\ 3z & 3w \end{bmatrix}


When adding matrices, add the elements in the same position:

[x612w]\begin{bmatrix} x & 6 \\ -1 & 2w \end{bmatrix} + [4x+yz+w3]\begin{bmatrix} 4 & x+y \\ z+w & 3 \end{bmatrix}

=[x+46+(x+y)1+(z+w)2w+3]= \begin{bmatrix} x+4 & 6+(x+y) \\ -1+(z+w) & 2w+3 \end{bmatrix}

=[x+4x+y+6z+w12w+3]= \begin{bmatrix} x+4 & x+y+6 \\ z+w-1 & 2w+3 \end{bmatrix}


The equation becomes:

[3x3y3z3w]\begin{bmatrix} 3x & 3y \\ 3z & 3w \end{bmatrix} = [x+4x+y+6z+w12w+3]\begin{bmatrix} x+4 & x+y+6 \\ z+w-1 & 2w+3 \end{bmatrix}

When two matrices are equal, their corresponding elements must be equal. This gives four equations:

3x=x+43x = x + 4

3y=x+y+63y = x + y + 6

3z=z+w13z = z + w - 1

3w=2w+33w = 2w + 3


From 3x=x+43x = x + 4:

3xx=43x - x = 4

2x=42x = 4

x=2x = 2


From 3w=2w+33w = 2w + 3:

3w2w=33w - 2w = 3

w=3w = 3


From 3y=x+y+63y = x + y + 6, substituting x=2x = 2:

3y=2+y+63y = 2 + y + 6

3yy=83y - y = 8

2y=82y = 8

y=4y = 4


From 3z=z+w13z = z + w - 1, substituting w=3w = 3:

3z=z+313z = z + 3 - 1

3zz=23z - z = 2

2z=22z = 2

z=1z = 1


Therefore, x=2x = 2, y=4y = 4, z=1z = 1, and w=3w = 3.

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