Find the values of [tex]\( a \)[/tex] and [tex]\( b \)[/tex] if

(a) [tex]\(\left[\begin{array}{ll}2 & b\end{array}\right] + \left[\begin{array}{ll}a & -1\end{array}\right] = \left[\begin{array}{ll}1 & 2\end{array}\right]\)[/tex]

(b) [tex]\(\left[\begin{array}{ll}a-1 & b+1\end{array}\right] - \left[\begin{array}{ll}1 & 2\end{array}\right] = \left[\begin{array}{ll}-2 & 1\end{array}\right]\)[/tex]

(c) [tex]\(\left[\begin{array}{ll}a+2 & 3\end{array}\right] + \left[\begin{array}{ll}-1 & 2+b\end{array}\right] = \left[\begin{array}{ll}3 & 0\end{array}\right]\)[/tex]



Answer :

Sure! Let's solve for the values of [tex]\(a\)[/tex] and [tex]\(b\)[/tex] for each part of the problem step by step.

### Part (a)
We start with the equation:
[tex]\[ \begin{bmatrix} 2 & b \end{bmatrix} + \begin{bmatrix} a & -1 \end{bmatrix} = \begin{bmatrix} 1 & 2 \end{bmatrix} \][/tex]

This leads to two separate equations:

1. [tex]\(2 + a = 1\)[/tex]
2. [tex]\(b - 1 = 2\)[/tex]

Solving these:

1. [tex]\(2 + a = 1 \Rightarrow a = 1 - 2 \Rightarrow a = -1\)[/tex]
2. [tex]\(b - 1 = 2 \Rightarrow b = 2 + 1 \Rightarrow b = 3\)[/tex]

So the solution for part (a) is:
[tex]\[ a = -1, \quad b = 3 \][/tex]

### Part (b)
Next, we consider the equation:
[tex]\[ \begin{bmatrix} a - 1 & b + 1 \end{bmatrix} - \begin{bmatrix} 1 & 2 \end{bmatrix} = \begin{bmatrix} -2 & 1 \end{bmatrix} \][/tex]

This leads to two equations:

1. [tex]\((a - 1) - 1 = -2\)[/tex]
2. [tex]\((b + 1) - 2 = 1\)[/tex]

Solving these:

1. [tex]\(a - 2 = -2 \Rightarrow a = -2 + 2 \Rightarrow a = 0\)[/tex]
2. [tex]\(b - 1 = 1 \Rightarrow b = 1 + 1 \Rightarrow b = 2\)[/tex]

So the solution for part (b) is:
[tex]\[ a = 0, \quad b = 2 \][/tex]

### Part (c)
Finally, we consider the equation:
[tex]\[ \begin{bmatrix} a + 2 & 3 \end{bmatrix} + \begin{bmatrix} -1 & 2 + b \end{bmatrix} = \begin{bmatrix} 3 & 0 \end{bmatrix} \][/tex]

This leads to two equations:

1. [tex]\(a + 2 - 1 = 3\)[/tex]
2. [tex]\(3 + (2 + b) = 0\)[/tex]

Solving these:

1. [tex]\(a + 1 = 3 \Rightarrow a = 3 - 1 \Rightarrow a = 2\)[/tex]
2. [tex]\(3 + 2 + b = 0 \Rightarrow 5 + b = 0 \Rightarrow b = -5\)[/tex]

So the solution for part (c) is:
[tex]\[ a = 2, \quad b = -5 \][/tex]

### Summary
The values of [tex]\(a\)[/tex] and [tex]\(b\)[/tex] for each part are:

- Part (a): [tex]\((a, b) = (-1, 3)\)[/tex]
- Part (b): [tex]\((a, b) = (0, 2)\)[/tex]
- Part (c): [tex]\((a, b) = (2, -5)\)[/tex]

Hence, the solutions are:

[tex]\[ ((-1, 3), (0, 2), (2, -5)) \][/tex]