Lettervormen getalwaarde

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Bereken de getalwaarde

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

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Bereken de getalwaarde

Verbetersleutel

1. \(\begin{align} a+4b&=1.a+4.b \text{ [met a = 4 en b = -2]}\\&=1.4+4.(-2)\\&=-4\\ \end{align}\)
2. \(\begin{align} 2a^2-5b&=2.a^2-5.b \text{ [met a = 4 en b = 3]}\\&=2.4^2-5.3\\&=17\\ \end{align}\)
3. \(\begin{align} ab+2b-9&=1.a.b+2.b-9 \text{ [met a = 1 en b = 2]}\\&=1.1.2+2.2-9\\&=-3\\ \end{align}\)
4. \(\begin{align} 4a^2-2b&=4.a^2-2.b \text{ [met a = -3 en b = 5]}\\&=4.(-3)^2-2.5\\&=26\\ \end{align}\)
5. \(\begin{align} 4a^2+6b&=4.a^2+6.b \text{ [met a = 6 en b = 6]}\\&=4.6^2+6.6\\&=180\\ \end{align}\)
6. \(\begin{align} 9a+b&=9.a+1.b \text{ [met a = 1 en b = -4]}\\&=9.1+1.(-4)\\&=5\\ \end{align}\)
7. \(\begin{align} 4a-b&=4.a-1.b \text{ [met a = 1 en b = -4]}\\&=4.1-1.(-4)\\&=8\\ \end{align}\)
8. \(\begin{align} 5a+5b&=5.a+5.b \text{ [met a = 2 en b = 2]}\\&=5.2+5.2\\&=20\\ \end{align}\)
9. \(\begin{align} 4a^2+b&=4.a^2+1.b \text{ [met a = -3 en b = 3]}\\&=4.(-3)^2+1.3\\&=39\\ \end{align}\)
10. \(\begin{align} 5a^2-2b&=5.a^2-2.b \text{ [met a = 5 en b = 2]}\\&=5.5^2-2.2\\&=121\\ \end{align}\)
11. \(\begin{align} 5a^2-4b&=5.a^2-4.b \text{ [met a = 1 en b = 2]}\\&=5.1^2-4.2\\&=-3\\ \end{align}\)
12. \(\begin{align} 2ab+b+1&=2.a.b+1.b+1 \text{ [met a = -3 en b = -2]}\\&=2.(-3).(-2)+1.(-2)+1\\&=11\\ \end{align}\)