Los de vierkantsvergelijking op zonder de discriminant te gebruiken
- \(-2x^2-2=0\)
- \(-7x^2-700=0\)
- \(6x^2-864=0\)
- \(-11x^2+188=-6x^2+8\)
- \(-5(-9x^2+3)=-(-40x^2-5)\)
- \(12x^2+1809=4x^2+9\)
- \(x^2-109=-3x^2-9\)
- \(3(-6x^2-3)=-(23x^2+14)\)
- \(-x^2+212=-7x^2-4\)
- \(4x^2-16=0\)
- \(7x^2-343=0\)
- \(-8x^2-512=0\)
Los de vierkantsvergelijking op zonder de discriminant te gebruiken
Verbetersleutel
- \(-2x^2-2=0 \\
\Leftrightarrow -2x^2 = 2 \\
\Leftrightarrow x^2 = \frac{2}{-2} < 0 \\
V = \varnothing \\ -----------------\)
- \(-7x^2-700=0 \\
\Leftrightarrow -7x^2 = 700 \\
\Leftrightarrow x^2 = \frac{700}{-7} < 0 \\
V = \varnothing \\ -----------------\)
- \(6x^2-864=0 \\
\Leftrightarrow 6x^2 = 864 \\
\Leftrightarrow x^2 = \frac{864}{6}=144 \\
\Leftrightarrow x = 12 \vee x = -12 \\
V = \Big\{-12, 12 \Big\} \\ -----------------\)
- \(-11x^2+188=-6x^2+8 \\ \Leftrightarrow -11x^2+6x^2=8-188 \\
\Leftrightarrow -5x^2 = -180 \\
\Leftrightarrow x^2 = \frac{-180}{-5}=36 \\
\Leftrightarrow x = 6 \vee x = -6 \\
V = \Big\{-6, 6 \Big\} \\ -----------------\)
- \(-5(-9x^2+3)=-(-40x^2-5) \\ \Leftrightarrow 45x^2-15=40x^2+5 \\
\Leftrightarrow 45x^2-40x^2=5+15 \\
\Leftrightarrow 5x^2 = 20 \\
\Leftrightarrow x^2 = \frac{20}{5}=4 \\
\Leftrightarrow x = 2 \vee x = -2 \\
V = \Big\{-2, 2 \Big\} \\ -----------------\)
- \(12x^2+1809=4x^2+9 \\ \Leftrightarrow 12x^2-4x^2=9-1809 \\
\Leftrightarrow 8x^2 = -1800 \\
\Leftrightarrow x^2 = \frac{-1800}{8} < 0 \\
V = \varnothing \\ -----------------\)
- \(x^2-109=-3x^2-9 \\ \Leftrightarrow x^2+3x^2=-9+109 \\
\Leftrightarrow 4x^2 = 100 \\
\Leftrightarrow x^2 = \frac{100}{4}=25 \\
\Leftrightarrow x = 5 \vee x = -5 \\
V = \Big\{-5, 5 \Big\} \\ -----------------\)
- \(3(-6x^2-3)=-(23x^2+14) \\ \Leftrightarrow -18x^2-9=-23x^2-14 \\
\Leftrightarrow -18x^2+23x^2=-14+9 \\
\Leftrightarrow 5x^2 = -5 \\
\Leftrightarrow x^2 = \frac{-5}{5} < 0 \\
V = \varnothing \\ -----------------\)
- \(-x^2+212=-7x^2-4 \\ \Leftrightarrow -x^2+7x^2=-4-212 \\
\Leftrightarrow 6x^2 = -216 \\
\Leftrightarrow x^2 = \frac{-216}{6} < 0 \\
V = \varnothing \\ -----------------\)
- \(4x^2-16=0 \\
\Leftrightarrow 4x^2 = 16 \\
\Leftrightarrow x^2 = \frac{16}{4}=4 \\
\Leftrightarrow x = 2 \vee x = -2 \\
V = \Big\{-2, 2 \Big\} \\ -----------------\)
- \(7x^2-343=0 \\
\Leftrightarrow 7x^2 = 343 \\
\Leftrightarrow x^2 = \frac{343}{7}=49 \\
\Leftrightarrow x = 7 \vee x = -7 \\
V = \Big\{-7, 7 \Big\} \\ -----------------\)
- \(-8x^2-512=0 \\
\Leftrightarrow -8x^2 = 512 \\
\Leftrightarrow x^2 = \frac{512}{-8} < 0 \\
V = \varnothing \\ -----------------\)