1. **Stating the problem:** We have the system of equations:
$$3x - 2y = a$$
$$ax + by = 10$$
with the solution $x = -2$ and $y = -1$. We need to find the values of $a$ and $b$.
2. **Substitute the solution into the first equation:**
$$3(-2) - 2(-1) = a$$
$$-6 + 2 = a$$
$$a = -4$$
3. **Substitute the solution and $a$ into the second equation:**
$$(-4)(-2) + b(-1) = 10$$
$$8 - b = 10$$
4. **Solve for $b$:**
$$8 - b = 10$$
$$-b = 10 - 8$$
$$-b = 2$$
$$b = -2$$
5. **Final answer:**
$$a = -4, \quad b = -2$$
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**b) Solve the system graphically:**
The system is:
$$3x - 2y = -4$$
$$-4x - 2y = 10$$
Rewrite each equation in slope-intercept form $y = mx + c$:
For the first equation:
$$3x - 2y = -4$$
$$-2y = -3x - 4$$
$$y = \frac{3}{2}x + 2$$
For the second equation:
$$-4x - 2y = 10$$
$$-2y = 4x + 10$$
$$y = -2x - 5$$
Plotting these two lines will show their intersection point.
Using a graphing tool, the intersection point is approximately:
$$x = -2.00, \quad y = -1.00$$
This matches the given solution.
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**Summary:**
- $a = -4$
- $b = -2$
- Graphical solution confirms $x = -2.00$, $y = -1.00$
Solve System E77981
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