1. | a. | 2(x
- 1)2 + 12 = 44 2(x - 1)2 = 32 (x - 1)2 = 16 x - 1 = 4 ∨ x - 1 = -4 x = 5 ∨ x = -3 |
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b. | 4x2 + 8
= -2x2 + 13 6x2 = 5 x2 = 5/6 x = √5/6 ∨ x = -√5/6 |
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c. | 4(2x + 3)2
+ 1 = 37 4(2x + 3)2 = 36 (2x + 3)2 = 9 2x + 3 = 3 ∨ 2x + 3 = -3 2x = 0 ∨ 2x = -6 x = 0 ∨ x = -3 |
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d. | 6 -
3(x + 8)2 = 3 -3(x + 8)2 = -3 (x + 8)2 = 1 x + 8 = 1 ∨ x + 8 = -1 x= -7 ∨ x = -9 |
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e. | 5x2 + 8 = 12
-
2x2 7x2 = 4 x2 = 4/7 x = √4/7 ∨ x = -√4/7 |
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f. | 2x(x + 3) = 7x2
+ 6x - 10 2x2 + 6x = 7x2 + 6x - 10 -5x2 = -10 x2 = 2 x = ±√2 |
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2 | a. | 2(x + 8)2
+ 20 = 5(x + 8)2 + 8 12 = 3(x + 8)2 (x + 8)2 = 4 x + 8 = 2 ∨ x + 8 = -2 x = -6 ∨ x = -10 |
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b. | 45
- 2(2x -
1)2 = (2x - 1)2
+ 18 27 = 3(2x - 1)2 (2x - 1)2 = 9 2x - 1 = 3 ∨ 2x - 1 = -3 2x = 4 ∨ 2x = -2 x = 2 ∨ x = -1 |
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c. |
2(x2 -
1)2
=
50 (x2 - 1)2 = 25 x2 - 1 = 5 ∨ x2 - 1 = -5 x2 = 6 ∨ x2 = -4 x = √6 ∨ x = -√6 (en x2 = -4 geeft geen oplossingen) |
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d. | 6 + (2x2 -
12)2 = 10 (2x2 - 12)2 = 4 2x2 - 12 = 2 ∨ 2x2 - 12 = -2 2x2 = 14 ∨ 2x2 = 10 x2 = 7 ∨ x2 = 5 x = √7 ∨ x = -√7 ∨ x = √5 ∨ x = -√5 |
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3. | Het midden van PR
ligt bij x = 1/2a Dan is y = 8 - 1/2x2 = 8 - 1/2(1/2a)2 = 8 - 1/8a2 Maar dat moet zijn y = 4, want het is het midden van PR. dus moet gelden 8 - 1/8a2 = 4 4 = 1/8a2 ⇒ a2 = 32 ⇒ a = √32 |
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4. | (x2
- 7)2 - 25 = 0 (x2 - 7)2 = 25 x2 - 7 = 5 ∨ x2 - 7 = -5 x2 = 12 ∨ x2 = 2 x = √12 ∨ x = -√12 ∨ x = √2 ∨ x = -√2 AD = 2√12 en BC = 2√2 Dus AD is 2√12/2√2 = √6 keer zo lang als BC. |
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