Lettervormen getalwaarde

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Bereken de getalwaarde

1. \(ab-5b+1\text{ [met a = -1 en b = 2]}\)
2. \(2a^2-b\text{ [met a = -2 en b = 2]}\)
3. \(4a-2b\text{ [met a = 3 en b = -2]}\)
4. \(3a^2-4b\text{ [met a = -5 en b = -1]}\)
5. \(5a-6b\text{ [met a = 5 en b = -2]}\)
6. \(9a-6b\text{ [met a = 3 en b = -5]}\)
7. \(5a^2-4b\text{ [met a = 4 en b = -1]}\)
8. \(2ab+2b-11\text{ [met a = 1 en b = -3]}\)
9. \(3a+9b\text{ [met a = -2 en b = -1]}\)
10. \(4ab+3b-15\text{ [met a = 2 en b = -1]}\)
11. \(5a-8b\text{ [met a = -1 en b = -5]}\)
12. \(2a^2+2b\text{ [met a = -1 en b = -3]}\)

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Bereken de getalwaarde

Verbetersleutel

1. \(\begin{align} ab-5b+1&=1.a.b-5.b+1 \text{ [met a = -1 en b = 2]}\\&=1.(-1).2-5.2+1\\&=-11\\ \end{align}\)
2. \(\begin{align} 2a^2-b&=2.a^2-1.b \text{ [met a = -2 en b = 2]}\\&=2.(-2)^2-1.2\\&=6\\ \end{align}\)
3. \(\begin{align} 4a-2b&=4.a-2.b \text{ [met a = 3 en b = -2]}\\&=4.3-2.(-2)\\&=16\\ \end{align}\)
4. \(\begin{align} 3a^2-4b&=3.a^2-4.b \text{ [met a = -5 en b = -1]}\\&=3.(-5)^2-4.(-1)\\&=79\\ \end{align}\)
5. \(\begin{align} 5a-6b&=5.a-6.b \text{ [met a = 5 en b = -2]}\\&=5.5-6.(-2)\\&=37\\ \end{align}\)
6. \(\begin{align} 9a-6b&=9.a-6.b \text{ [met a = 3 en b = -5]}\\&=9.3-6.(-5)\\&=57\\ \end{align}\)
7. \(\begin{align} 5a^2-4b&=5.a^2-4.b \text{ [met a = 4 en b = -1]}\\&=5.4^2-4.(-1)\\&=84\\ \end{align}\)
8. \(\begin{align} 2ab+2b-11&=2.a.b+2.b-11 \text{ [met a = 1 en b = -3]}\\&=2.1.(-3)+2.(-3)-11\\&=-23\\ \end{align}\)
9. \(\begin{align} 3a+9b&=3.a+9.b \text{ [met a = -2 en b = -1]}\\&=3.(-2)+9.(-1)\\&=-15\\ \end{align}\)
10. \(\begin{align} 4ab+3b-15&=4.a.b+3.b-15 \text{ [met a = 2 en b = -1]}\\&=4.2.(-1)+3.(-1)-15\\&=-26\\ \end{align}\)
11. \(\begin{align} 5a-8b&=5.a-8.b \text{ [met a = -1 en b = -5]}\\&=5.(-1)-8.(-5)\\&=35\\ \end{align}\)
12. \(\begin{align} 2a^2+2b&=2.a^2+2.b \text{ [met a = -1 en b = -3]}\\&=2.(-1)^2+2.(-3)\\&=-4\\ \end{align}\)