Lettervormen getalwaarde

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Bereken de getalwaarde

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

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Bereken de getalwaarde

Verbetersleutel

1. \(\begin{align} 4a+7b&=4.a+7.b \text{ [met a = -5 en b = -4]}\\&=4.(-5)+7.(-4)\\&=-48\\ \end{align}\)
2. \(\begin{align} 5a-8b&=5.a-8.b \text{ [met a = 4 en b = 5]}\\&=5.4-8.5\\&=-20\\ \end{align}\)
3. \(\begin{align} 4ab+2b-7&=4.a.b+2.b-7 \text{ [met a = -3 en b = 1]}\\&=4.(-3).1+2.1-7\\&=-17\\ \end{align}\)
4. \(\begin{align} ab+b-4&=1.a.b+1.b-4 \text{ [met a = -1 en b = -5]}\\&=1.(-1).(-5)+1.(-5)-4\\&=-4\\ \end{align}\)
5. \(\begin{align} 4ab+b-5&=4.a.b+1.b-5 \text{ [met a = 2 en b = 4]}\\&=4.2.4+1.4-5\\&=31\\ \end{align}\)
6. \(\begin{align} 4a-b&=4.a-1.b \text{ [met a = -3 en b = 4]}\\&=4.(-3)-1.4\\&=-16\\ \end{align}\)
7. \(\begin{align} 3a^2+b&=3.a^2+1.b \text{ [met a = -5 en b = -3]}\\&=3.(-5)^2+1.(-3)\\&=72\\ \end{align}\)
8. \(\begin{align} 2a^2+2b&=2.a^2+2.b \text{ [met a = -5 en b = -4]}\\&=2.(-5)^2+2.(-4)\\&=42\\ \end{align}\)
9. \(\begin{align} 2a^2-5b&=2.a^2-5.b \text{ [met a = 4 en b = 6]}\\&=2.4^2-5.6\\&=2\\ \end{align}\)
10. \(\begin{align} a^2+3b&=1.a^2+3.b \text{ [met a = -2 en b = -5]}\\&=1.(-2)^2+3.(-5)\\&=-11\\ \end{align}\)
11. \(\begin{align} 2a^2+6b&=2.a^2+6.b \text{ [met a = -2 en b = -3]}\\&=2.(-2)^2+6.(-3)\\&=-10\\ \end{align}\)
12. \(\begin{align} 10a-7b&=10.a-7.b \text{ [met a = 2 en b = 2]}\\&=10.2-7.2\\&=6\\ \end{align}\)