Los de vierkantsvergelijking op zonder de discriminant te gebruiken
- \(7x^2-203=9x^2-3\)
- \(4(-6x^2+2)=-(31x^2-1380)\)
- \(-6x^2-135=-8x^2-7\)
- \(10x^2-141=6x^2+3\)
- \(5x^2-4=3x^2-4\)
- \(5x^2-27=-3x^2+5\)
- \(5(-8x^2+9)=-(46x^2-1395)\)
- \(-2x^2-392=0\)
- \(-x^2+81=0\)
- \(-6x^2+1350=0\)
- \(2x^2-259=6x^2-3\)
- \(-4(5x^2+4)=-(18x^2+16)\)
Los de vierkantsvergelijking op zonder de discriminant te gebruiken
Verbetersleutel
- \(7x^2-203=9x^2-3 \\ \Leftrightarrow 7x^2-9x^2=-3+203 \\
\Leftrightarrow -2x^2 = 200 \\
\Leftrightarrow x^2 = \frac{200}{-2} < 0 \\
V = \varnothing \\ -----------------\)
- \(4(-6x^2+2)=-(31x^2-1380) \\ \Leftrightarrow -24x^2+8=-31x^2+1380 \\
\Leftrightarrow -24x^2+31x^2=1380-8 \\
\Leftrightarrow 7x^2 = 1372 \\
\Leftrightarrow x^2 = \frac{1372}{7}=196 \\
\Leftrightarrow x = 14 \vee x = -14 \\
V = \Big\{-14, 14 \Big\} \\ -----------------\)
- \(-6x^2-135=-8x^2-7 \\ \Leftrightarrow -6x^2+8x^2=-7+135 \\
\Leftrightarrow 2x^2 = 128 \\
\Leftrightarrow x^2 = \frac{128}{2}=64 \\
\Leftrightarrow x = 8 \vee x = -8 \\
V = \Big\{-8, 8 \Big\} \\ -----------------\)
- \(10x^2-141=6x^2+3 \\ \Leftrightarrow 10x^2-6x^2=3+141 \\
\Leftrightarrow 4x^2 = 144 \\
\Leftrightarrow x^2 = \frac{144}{4}=36 \\
\Leftrightarrow x = 6 \vee x = -6 \\
V = \Big\{-6, 6 \Big\} \\ -----------------\)
- \(5x^2-4=3x^2-4 \\ \Leftrightarrow 5x^2-3x^2=-4+4 \\
\Leftrightarrow 2x^2 = 0 \\
\Leftrightarrow x^2 = \frac{0}{2}\\
\Leftrightarrow x = 0 \\
V = \Big\{ 0 \Big\} \\ -----------------\)
- \(5x^2-27=-3x^2+5 \\ \Leftrightarrow 5x^2+3x^2=5+27 \\
\Leftrightarrow 8x^2 = 32 \\
\Leftrightarrow x^2 = \frac{32}{8}=4 \\
\Leftrightarrow x = 2 \vee x = -2 \\
V = \Big\{-2, 2 \Big\} \\ -----------------\)
- \(5(-8x^2+9)=-(46x^2-1395) \\ \Leftrightarrow -40x^2+45=-46x^2+1395 \\
\Leftrightarrow -40x^2+46x^2=1395-45 \\
\Leftrightarrow 6x^2 = 1350 \\
\Leftrightarrow x^2 = \frac{1350}{6}=225 \\
\Leftrightarrow x = 15 \vee x = -15 \\
V = \Big\{-15, 15 \Big\} \\ -----------------\)
- \(-2x^2-392=0 \\
\Leftrightarrow -2x^2 = 392 \\
\Leftrightarrow x^2 = \frac{392}{-2} < 0 \\
V = \varnothing \\ -----------------\)
- \(-x^2+81=0 \\
\Leftrightarrow -x^2 = -81 \\
\Leftrightarrow x^2 = \frac{-81}{-1}=81 \\
\Leftrightarrow x = 9 \vee x = -9 \\
V = \Big\{-9, 9 \Big\} \\ -----------------\)
- \(-6x^2+1350=0 \\
\Leftrightarrow -6x^2 = -1350 \\
\Leftrightarrow x^2 = \frac{-1350}{-6}=225 \\
\Leftrightarrow x = 15 \vee x = -15 \\
V = \Big\{-15, 15 \Big\} \\ -----------------\)
- \(2x^2-259=6x^2-3 \\ \Leftrightarrow 2x^2-6x^2=-3+259 \\
\Leftrightarrow -4x^2 = 256 \\
\Leftrightarrow x^2 = \frac{256}{-4} < 0 \\
V = \varnothing \\ -----------------\)
- \(-4(5x^2+4)=-(18x^2+16) \\ \Leftrightarrow -20x^2-16=-18x^2-16 \\
\Leftrightarrow -20x^2+18x^2=-16+16 \\
\Leftrightarrow -2x^2 = 0 \\
\Leftrightarrow x^2 = \frac{0}{-2}\\
\Leftrightarrow x = 0 \\
V = \Big\{ 0 \Big\} \\ -----------------\)