1. **Problem a:** Solve the equation $$\sqrt{4x - 7} + 2 = 5$$
2. **Step 1:** Isolate the square root term:
$$\sqrt{4x - 7} = 5 - 2 = 3$$
3. **Step 2:** Square both sides to eliminate the square root:
$$4x - 7 = 3^2 = 9$$
4. **Step 3:** Solve for $x$:
$$4x = 9 + 7 = 16$$
$$x = \frac{16}{4} = 4$$
5. **Step 4:** Check the solution in the original equation to avoid extraneous roots:
$$\sqrt{4(4) - 7} + 2 = \sqrt{16 - 7} + 2 = \sqrt{9} + 2 = 3 + 2 = 5$$
Solution $x=4$ is valid.
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6. **Problem b:** Solve the quadratic equation $$-x^2 + 2x - 2 = 0$$ using the quadratic formula.
7. **Step 1:** Write the quadratic in standard form:
$$-x^2 + 2x - 2 = 0$$
Coefficients: $a = -1$, $b = 2$, $c = -2$
8. **Step 2:** Quadratic formula:
$$x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}$$
9. **Step 3:** Calculate the discriminant:
$$\Delta = b^2 - 4ac = 2^2 - 4(-1)(-2) = 4 - 8 = -4$$
10. **Step 4:** Since $\Delta < 0$, there are no real solutions; solutions are complex:
$$x = \frac{-2 \pm \sqrt{-4}}{2(-1)} = \frac{-2 \pm 2i}{-2} = 1 \mp i$$
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11. **Problem 4a:** Write the equation of the circle $$x^2 + y^2 + 10x - 14y + 21 = 0$$ in standard form and identify center and radius.
12. **Step 1:** Group $x$ and $y$ terms:
$$ (x^2 + 10x) + (y^2 - 14y) = -21 $$
13. **Step 2:** Complete the square for $x$ and $y$:
- For $x$: half of 10 is 5, square is 25
- For $y$: half of -14 is -7, square is 49
Add 25 and 49 to both sides:
$$ (x^2 + 10x + 25) + (y^2 - 14y + 49) = -21 + 25 + 49 $$
14. **Step 3:** Write as squares:
$$ (x + 5)^2 + (y - 7)^2 = 53 $$
15. **Step 4:** Identify center and radius:
Center: $(-5, 7)$
Radius: $\sqrt{53}$
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16. **Problem 4b:** Determine the vertex and axis of symmetry of the parabola defined by
$$f(x) = 2x^2 - 8x + 6$$
17. **Step 1:** Use vertex formula:
$$x_{vertex} = -\frac{b}{2a} = -\frac{-8}{2 \times 2} = \frac{8}{4} = 2$$
18. **Step 2:** Find $y$ coordinate of vertex:
$$f(2) = 2(2)^2 - 8(2) + 6 = 8 - 16 + 6 = -2$$
19. **Step 3:** Vertex is at $(2, -2)$
20. **Step 4:** Axis of symmetry is the vertical line through the vertex:
$$x = 2$$
Equations Circles Parabolas
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