1. Problem 49: Find the number of intersection points between $y = \sqrt{|x|}$ and $5y = x + 6$.
2. Problem 50: Find the number of intersection points between $y = |x^2 - 4|$ and $y = \frac{x^2}{2} + 4$.
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### Problem 49
1. State the problem: Find intersections of $y = \sqrt{|x|}$ and $5y = x + 6$.
2. Express $y$ from the second equation: $y = \frac{x + 6}{5}$.
3. Set equal: $\sqrt{|x|} = \frac{x + 6}{5}$.
4. Square both sides: $|x| = \left(\frac{x + 6}{5}\right)^2 = \frac{(x + 6)^2}{25}$.
5. Multiply both sides by 25: $25|x| = (x + 6)^2$.
6. Consider two cases for $|x|$:
- Case 1: $x \geq 0$, then $25x = (x + 6)^2$.
- Case 2: $x < 0$, then $-25x = (x + 6)^2$.
7. Solve Case 1:
$25x = x^2 + 12x + 36$.
Rearrange: $x^2 - 13x + 36 = 0$.
Factor or use quadratic formula:
$x = \frac{13 \pm \sqrt{169 - 144}}{2} = \frac{13 \pm 5}{2}$.
Solutions: $x = 9$ or $x = 4$ (both $\geq 0$ valid).
8. Solve Case 2:
$-25x = x^2 + 12x + 36$.
Rearrange: $x^2 + 37x + 36 = 0$.
Use quadratic formula:
$x = \frac{-37 \pm \sqrt{37^2 - 4 \cdot 36}}{2} = \frac{-37 \pm \sqrt{1369 - 144}}{2} = \frac{-37 \pm \sqrt{1225}}{2} = \frac{-37 \pm 35}{2}$.
Solutions: $x = -1$ or $x = -36$ (both $< 0$ valid).
9. Total valid $x$ values: $-36, -1, 4, 9$.
10. Find corresponding $y$ values using $y = \frac{x + 6}{5}$:
- For $x = -36$, $y = \frac{-36 + 6}{5} = \frac{-30}{5} = -6$ (Check $y = \sqrt{|x|} = \sqrt{36} = 6$, mismatch in sign, discard).
- For $x = -1$, $y = \frac{-1 + 6}{5} = 1$ (Check $\sqrt{1} = 1$, valid).
- For $x = 4$, $y = \frac{4 + 6}{5} = 2$ (Check $\sqrt{4} = 2$, valid).
- For $x = 9$, $y = \frac{9 + 6}{5} = 3$ (Check $\sqrt{9} = 3$, valid).
11. Valid intersection points: $( -1, 1 ), (4, 2), (9, 3)$.
12. Number of intersection points: **3**.
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### Problem 50
1. State the problem: Find intersections of $y = |x^2 - 4|$ and $y = \frac{x^2}{2} + 4$.
2. Set equal: $|x^2 - 4| = \frac{x^2}{2} + 4$.
3. Consider two cases for absolute value:
- Case 1: $x^2 - 4 \geq 0 \Rightarrow |x^2 - 4| = x^2 - 4$.
- Case 2: $x^2 - 4 < 0 \Rightarrow |x^2 - 4| = -(x^2 - 4) = 4 - x^2$.
4. Case 1 ($x^2 \geq 4$):
$x^2 - 4 = \frac{x^2}{2} + 4$.
Rearrange:
$x^2 - \frac{x^2}{2} = 4 + 4$.
$\frac{x^2}{2} = 8$.
$x^2 = 16$.
So $x = \pm 4$.
Check condition $x^2 \geq 4$ holds.
5. Case 2 ($x^2 < 4$):
$4 - x^2 = \frac{x^2}{2} + 4$.
Rearrange:
$4 - x^2 - \frac{x^2}{2} = 4$.
$-\frac{3x^2}{2} = 0$.
$x^2 = 0$.
So $x = 0$.
Check condition $x^2 < 4$ holds.
6. Intersection points at $x = -4, 0, 4$.
7. Find $y$ values:
- At $x = -4$: $y = \frac{16}{2} + 4 = 8 + 4 = 12$.
- At $x = 0$: $y = \frac{0}{2} + 4 = 4$.
- At $x = 4$: $y = 12$.
8. Number of intersection points: **3**.
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Final answers:
- Problem 49: 3 intersection points.
- Problem 50: 3 intersection points.
Intersection Points Ad5B45
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