Los de vierkantsvergelijking op zonder de discriminant te gebruiken
- \(-7x^2+567=0\)
- \(-4x^2+8=-3x^2+8\)
- \(5(-7x^2-9)=-(43x^2+77)\)
- \(3(-9x^2-9)=-(23x^2-873)\)
- \(8x^2-1568=0\)
- \(-6x^2+1176=0\)
- \(6x^2-13=2x^2-9\)
- \(8x^2-648=0\)
- \(-3(-8x^2+10)=-(-23x^2+26)\)
- \(-4(-5x^2+3)=-(-24x^2+12)\)
- \(4(-5x^2+2)=-(28x^2-808)\)
- \(-2x^2+315=2x^2-9\)
Los de vierkantsvergelijking op zonder de discriminant te gebruiken
Verbetersleutel
- \(-7x^2+567=0 \\
\Leftrightarrow -7x^2 = -567 \\
\Leftrightarrow x^2 = \frac{-567}{-7}=81 \\
\Leftrightarrow x = 9 \vee x = -9 \\
V = \Big\{-9, 9 \Big\} \\ -----------------\)
- \(-4x^2+8=-3x^2+8 \\ \Leftrightarrow -4x^2+3x^2=8-8 \\
\Leftrightarrow -x^2 = 0 \\
\Leftrightarrow x^2 = \frac{0}{-1}\\
\Leftrightarrow x = 0 \\
V = \Big\{ 0 \Big\} \\ -----------------\)
- \(5(-7x^2-9)=-(43x^2+77) \\ \Leftrightarrow -35x^2-45=-43x^2-77 \\
\Leftrightarrow -35x^2+43x^2=-77+45 \\
\Leftrightarrow 8x^2 = -32 \\
\Leftrightarrow x^2 = \frac{-32}{8} < 0 \\
V = \varnothing \\ -----------------\)
- \(3(-9x^2-9)=-(23x^2-873) \\ \Leftrightarrow -27x^2-27=-23x^2+873 \\
\Leftrightarrow -27x^2+23x^2=873+27 \\
\Leftrightarrow -4x^2 = 900 \\
\Leftrightarrow x^2 = \frac{900}{-4} < 0 \\
V = \varnothing \\ -----------------\)
- \(8x^2-1568=0 \\
\Leftrightarrow 8x^2 = 1568 \\
\Leftrightarrow x^2 = \frac{1568}{8}=196 \\
\Leftrightarrow x = 14 \vee x = -14 \\
V = \Big\{-14, 14 \Big\} \\ -----------------\)
- \(-6x^2+1176=0 \\
\Leftrightarrow -6x^2 = -1176 \\
\Leftrightarrow x^2 = \frac{-1176}{-6}=196 \\
\Leftrightarrow x = 14 \vee x = -14 \\
V = \Big\{-14, 14 \Big\} \\ -----------------\)
- \(6x^2-13=2x^2-9 \\ \Leftrightarrow 6x^2-2x^2=-9+13 \\
\Leftrightarrow 4x^2 = 4 \\
\Leftrightarrow x^2 = \frac{4}{4}=1 \\
\Leftrightarrow x = 1 \vee x = -1 \\
V = \Big\{-1, 1 \Big\} \\ -----------------\)
- \(8x^2-648=0 \\
\Leftrightarrow 8x^2 = 648 \\
\Leftrightarrow x^2 = \frac{648}{8}=81 \\
\Leftrightarrow x = 9 \vee x = -9 \\
V = \Big\{-9, 9 \Big\} \\ -----------------\)
- \(-3(-8x^2+10)=-(-23x^2+26) \\ \Leftrightarrow 24x^2-30=23x^2-26 \\
\Leftrightarrow 24x^2-23x^2=-26+30 \\
\Leftrightarrow x^2 = 4 \\
\Leftrightarrow x^2 = \frac{4}{1}=4 \\
\Leftrightarrow x = 2 \vee x = -2 \\
V = \Big\{-2, 2 \Big\} \\ -----------------\)
- \(-4(-5x^2+3)=-(-24x^2+12) \\ \Leftrightarrow 20x^2-12=24x^2-12 \\
\Leftrightarrow 20x^2-24x^2=-12+12 \\
\Leftrightarrow -4x^2 = 0 \\
\Leftrightarrow x^2 = \frac{0}{-4}\\
\Leftrightarrow x = 0 \\
V = \Big\{ 0 \Big\} \\ -----------------\)
- \(4(-5x^2+2)=-(28x^2-808) \\ \Leftrightarrow -20x^2+8=-28x^2+808 \\
\Leftrightarrow -20x^2+28x^2=808-8 \\
\Leftrightarrow 8x^2 = 800 \\
\Leftrightarrow x^2 = \frac{800}{8}=100 \\
\Leftrightarrow x = 10 \vee x = -10 \\
V = \Big\{-10, 10 \Big\} \\ -----------------\)
- \(-2x^2+315=2x^2-9 \\ \Leftrightarrow -2x^2-2x^2=-9-315 \\
\Leftrightarrow -4x^2 = -324 \\
\Leftrightarrow x^2 = \frac{-324}{-4}=81 \\
\Leftrightarrow x = 9 \vee x = -9 \\
V = \Big\{-9, 9 \Big\} \\ -----------------\)