Lettervormen getalwaarde

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Bereken de getalwaarde

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

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Bereken de getalwaarde

Verbetersleutel

1. \(\begin{align} ab+5b+7&=1.a.b+5.b+7 \text{ [met a = 1 en b = -2]}\\&=1.1.(-2)+5.(-2)+7\\&=-5\\ \end{align}\)
2. \(\begin{align} 2ab+b+7&=2.a.b+1.b+7 \text{ [met a = -1 en b = -3]}\\&=2.(-1).(-3)+1.(-3)+7\\&=10\\ \end{align}\)
3. \(\begin{align} 2a^2+b&=2.a^2+1.b \text{ [met a = 4 en b = -3]}\\&=2.4^2+1.(-3)\\&=29\\ \end{align}\)
4. \(\begin{align} 5ab-2b+8&=5.a.b-2.b+8 \text{ [met a = 2 en b = 3]}\\&=5.2.3-2.3+8\\&=32\\ \end{align}\)
5. \(\begin{align} a-3b&=1.a-3.b \text{ [met a = -4 en b = 3]}\\&=1.(-4)-3.3\\&=-13\\ \end{align}\)
6. \(\begin{align} 2ab+4b+8&=2.a.b+4.b+8 \text{ [met a = -5 en b = 2]}\\&=2.(-5).2+4.2+8\\&=-4\\ \end{align}\)
7. \(\begin{align} a^2+4b&=1.a^2+4.b \text{ [met a = 4 en b = 1]}\\&=1.4^2+4.1\\&=20\\ \end{align}\)
8. \(\begin{align} 9a+3b&=9.a+3.b \text{ [met a = -5 en b = 2]}\\&=9.(-5)+3.2\\&=-39\\ \end{align}\)
9. \(\begin{align} 3a+10b&=3.a+10.b \text{ [met a = -1 en b = -3]}\\&=3.(-1)+10.(-3)\\&=-33\\ \end{align}\)
10. \(\begin{align} 4a-8b&=4.a-8.b \text{ [met a = 5 en b = 2]}\\&=4.5-8.2\\&=4\\ \end{align}\)
11. \(\begin{align} 3ab-4b-6&=3.a.b-4.b-6 \text{ [met a = 2 en b = 1]}\\&=3.2.1-4.1-6\\&=-4\\ \end{align}\)
12. \(\begin{align} 3a^2+b&=3.a^2+1.b \text{ [met a = 3 en b = -5]}\\&=3.3^2+1.(-5)\\&=22\\ \end{align}\)