1. **State the problem:**
We are given a system of linear equations:
$$2x - 3y = 7$$
$$3x + y = 5$$
and a 3x3 matrix:
$$\begin{bmatrix} 2 & -3 & 6 \\ 2 & -1 & 2 \\ -10 & 5 & 2 \end{bmatrix}$$
We need to solve the system and evaluate the determinant of the matrix.
2. **Solve the system of equations:**
The system is:
$$2x - 3y = 7 \quad (1)$$
$$3x + y = 5 \quad (2)$$
We can use substitution or elimination. Let's use substitution.
From equation (2):
$$y = 5 - 3x$$
Substitute into equation (1):
$$2x - 3(5 - 3x) = 7$$
$$2x - 15 + 9x = 7$$
$$11x - 15 = 7$$
$$11x = 7 + 15$$
$$11x = 22$$
$$x = \frac{22}{11}$$
$$x = 2$$
Substitute $x=2$ back into $y = 5 - 3x$:
$$y = 5 - 3(2)$$
$$y = 5 - 6$$
$$y = -1$$
3. **Evaluate the determinant of the matrix:**
The matrix is:
$$A = \begin{bmatrix} 2 & -3 & 6 \\ 2 & -1 & 2 \\ -10 & 5 & 2 \end{bmatrix}$$
The determinant of a 3x3 matrix $A = \begin{bmatrix} a & b & c \\ d & e & f \\ g & h & i \end{bmatrix}$ is:
$$\det(A) = a(ei - fh) - b(di - fg) + c(dh - eg)$$
Calculate each term:
$$a = 2, b = -3, c = 6$$
$$d = 2, e = -1, f = 2$$
$$g = -10, h = 5, i = 2$$
Calculate:
$$ei - fh = (-1)(2) - (2)(5) = -2 - 10 = -12$$
$$di - fg = (2)(2) - (2)(-10) = 4 + 20 = 24$$
$$dh - eg = (2)(5) - (-1)(-10) = 10 - 10 = 0$$
Now:
$$\det(A) = 2(-12) - (-3)(24) + 6(0) = -24 + 72 + 0 = 48$$
**Final answers:**
- Solution to the system: $x=2$, $y=-1$
- Determinant of the matrix: $48$
Solve System Determinant 979D90
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