Lettervormen getalwaarde

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Bereken de getalwaarde

1. \(3a^2-5b\text{ [met a = 3 en b = 4]}\)
2. \(a+6b\text{ [met a = -1 en b = 1]}\)
3. \(10a+8b\text{ [met a = -5 en b = -1]}\)
4. \(4a^2-6b\text{ [met a = 3 en b = -5]}\)
5. \(2ab-b-5\text{ [met a = 4 en b = -1]}\)
6. \(3ab+5b-5\text{ [met a = -3 en b = 5]}\)
7. \(2ab+5b+7\text{ [met a = 4 en b = -2]}\)
8. \(10a-7b\text{ [met a = -5 en b = 2]}\)
9. \(4a-5b\text{ [met a = 4 en b = 5]}\)
10. \(a+8b\text{ [met a = 5 en b = 2]}\)
11. \(4ab-2b-14\text{ [met a = 4 en b = 6]}\)
12. \(8a+7b\text{ [met a = 2 en b = -3]}\)

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Bereken de getalwaarde

Verbetersleutel

1. \(\begin{align} 3a^2-5b&=3.a^2-5.b \text{ [met a = 3 en b = 4]}\\&=3.3^2-5.4\\&=7\\ \end{align}\)
2. \(\begin{align} a+6b&=1.a+6.b \text{ [met a = -1 en b = 1]}\\&=1.(-1)+6.1\\&=5\\ \end{align}\)
3. \(\begin{align} 10a+8b&=10.a+8.b \text{ [met a = -5 en b = -1]}\\&=10.(-5)+8.(-1)\\&=-58\\ \end{align}\)
4. \(\begin{align} 4a^2-6b&=4.a^2-6.b \text{ [met a = 3 en b = -5]}\\&=4.3^2-6.(-5)\\&=66\\ \end{align}\)
5. \(\begin{align} 2ab-b-5&=2.a.b-1.b-5 \text{ [met a = 4 en b = -1]}\\&=2.4.(-1)-1.(-1)-5\\&=-12\\ \end{align}\)
6. \(\begin{align} 3ab+5b-5&=3.a.b+5.b-5 \text{ [met a = -3 en b = 5]}\\&=3.(-3).5+5.5-5\\&=-25\\ \end{align}\)
7. \(\begin{align} 2ab+5b+7&=2.a.b+5.b+7 \text{ [met a = 4 en b = -2]}\\&=2.4.(-2)+5.(-2)+7\\&=-19\\ \end{align}\)
8. \(\begin{align} 10a-7b&=10.a-7.b \text{ [met a = -5 en b = 2]}\\&=10.(-5)-7.2\\&=-64\\ \end{align}\)
9. \(\begin{align} 4a-5b&=4.a-5.b \text{ [met a = 4 en b = 5]}\\&=4.4-5.5\\&=-9\\ \end{align}\)
10. \(\begin{align} a+8b&=1.a+8.b \text{ [met a = 5 en b = 2]}\\&=1.5+8.2\\&=21\\ \end{align}\)
11. \(\begin{align} 4ab-2b-14&=4.a.b-2.b-14 \text{ [met a = 4 en b = 6]}\\&=4.4.6-2.6-14\\&=70\\ \end{align}\)
12. \(\begin{align} 8a+7b&=8.a+7.b \text{ [met a = 2 en b = -3]}\\&=8.2+7.(-3)\\&=-5\\ \end{align}\)