Lettervormen getalwaarde

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Bereken de getalwaarde

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

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Bereken de getalwaarde

Verbetersleutel

1. \(\begin{align} 2a+8b&=2.a+8.b \text{ [met a = -4 en b = 2]}\\&=2.(-4)+8.2\\&=8\\ \end{align}\)
2. \(\begin{align} 3a^2-2b&=3.a^2-2.b \text{ [met a = 1 en b = 1]}\\&=3.1^2-2.1\\&=1\\ \end{align}\)
3. \(\begin{align} a^2-2b&=1.a^2-2.b \text{ [met a = 1 en b = 4]}\\&=1.1^2-2.4\\&=-7\\ \end{align}\)
4. \(\begin{align} 5ab-b+11&=5.a.b-1.b+11 \text{ [met a = 4 en b = 1]}\\&=5.4.1-1.1+11\\&=30\\ \end{align}\)
5. \(\begin{align} 2a^2+3b&=2.a^2+3.b \text{ [met a = 3 en b = 3]}\\&=2.3^2+3.3\\&=27\\ \end{align}\)
6. \(\begin{align} 4a^2+5b&=4.a^2+5.b \text{ [met a = -3 en b = -2]}\\&=4.(-3)^2+5.(-2)\\&=26\\ \end{align}\)
7. \(\begin{align} 5ab-2b-6&=5.a.b-2.b-6 \text{ [met a = -5 en b = -4]}\\&=5.(-5).(-4)-2.(-4)-6\\&=102\\ \end{align}\)
8. \(\begin{align} 5a^2+4b&=5.a^2+4.b \text{ [met a = -5 en b = -1]}\\&=5.(-5)^2+4.(-1)\\&=121\\ \end{align}\)
9. \(\begin{align} a^2+b&=1.a^2+1.b \text{ [met a = 1 en b = 1]}\\&=1.1^2+1.1\\&=2\\ \end{align}\)
10. \(\begin{align} 3a^2+b&=3.a^2+1.b \text{ [met a = -4 en b = -5]}\\&=3.(-4)^2+1.(-5)\\&=43\\ \end{align}\)
11. \(\begin{align} 5ab-4b-5&=5.a.b-4.b-5 \text{ [met a = -1 en b = -1]}\\&=5.(-1).(-1)-4.(-1)-5\\&=4\\ \end{align}\)
12. \(\begin{align} ab+b+7&=1.a.b+1.b+7 \text{ [met a = 1 en b = 3]}\\&=1.1.3+1.3+7\\&=13\\ \end{align}\)