Los de vierkantsvergelijking op zonder de discriminant te gebruiken
- \(2x^2+2=0\)
- \(4x^2-158=-2x^2-8\)
- \(-9x^2-399=-7x^2-7\)
- \(-3(-2x^2+2)=-(-2x^2+490)\)
- \(8x^2+1152=0\)
- \(3(8x^2+4)=-(-18x^2+42)\)
- \(5(-8x^2+10)=-(45x^2-770)\)
- \(-11x^2-843=-6x^2+2\)
- \(-8x^2+22=-9x^2-3\)
- \(11x^2-286=5x^2+8\)
- \(-6x^2+54=0\)
- \(-9x^2+121=-4x^2-4\)
Los de vierkantsvergelijking op zonder de discriminant te gebruiken
Verbetersleutel
- \(2x^2+2=0 \\
\Leftrightarrow 2x^2 = -2 \\
\Leftrightarrow x^2 = \frac{-2}{2} < 0 \\
V = \varnothing \\ -----------------\)
- \(4x^2-158=-2x^2-8 \\ \Leftrightarrow 4x^2+2x^2=-8+158 \\
\Leftrightarrow 6x^2 = 150 \\
\Leftrightarrow x^2 = \frac{150}{6}=25 \\
\Leftrightarrow x = 5 \vee x = -5 \\
V = \Big\{-5, 5 \Big\} \\ -----------------\)
- \(-9x^2-399=-7x^2-7 \\ \Leftrightarrow -9x^2+7x^2=-7+399 \\
\Leftrightarrow -2x^2 = 392 \\
\Leftrightarrow x^2 = \frac{392}{-2} < 0 \\
V = \varnothing \\ -----------------\)
- \(-3(-2x^2+2)=-(-2x^2+490) \\ \Leftrightarrow 6x^2-6=2x^2-490 \\
\Leftrightarrow 6x^2-2x^2=-490+6 \\
\Leftrightarrow 4x^2 = -484 \\
\Leftrightarrow x^2 = \frac{-484}{4} < 0 \\
V = \varnothing \\ -----------------\)
- \(8x^2+1152=0 \\
\Leftrightarrow 8x^2 = -1152 \\
\Leftrightarrow x^2 = \frac{-1152}{8} < 0 \\
V = \varnothing \\ -----------------\)
- \(3(8x^2+4)=-(-18x^2+42) \\ \Leftrightarrow 24x^2+12=18x^2-42 \\
\Leftrightarrow 24x^2-18x^2=-42-12 \\
\Leftrightarrow 6x^2 = -54 \\
\Leftrightarrow x^2 = \frac{-54}{6} < 0 \\
V = \varnothing \\ -----------------\)
- \(5(-8x^2+10)=-(45x^2-770) \\ \Leftrightarrow -40x^2+50=-45x^2+770 \\
\Leftrightarrow -40x^2+45x^2=770-50 \\
\Leftrightarrow 5x^2 = 720 \\
\Leftrightarrow x^2 = \frac{720}{5}=144 \\
\Leftrightarrow x = 12 \vee x = -12 \\
V = \Big\{-12, 12 \Big\} \\ -----------------\)
- \(-11x^2-843=-6x^2+2 \\ \Leftrightarrow -11x^2+6x^2=2+843 \\
\Leftrightarrow -5x^2 = 845 \\
\Leftrightarrow x^2 = \frac{845}{-5} < 0 \\
V = \varnothing \\ -----------------\)
- \(-8x^2+22=-9x^2-3 \\ \Leftrightarrow -8x^2+9x^2=-3-22 \\
\Leftrightarrow x^2 = -25 \\
\Leftrightarrow x^2 = \frac{-25}{1} < 0 \\
V = \varnothing \\ -----------------\)
- \(11x^2-286=5x^2+8 \\ \Leftrightarrow 11x^2-5x^2=8+286 \\
\Leftrightarrow 6x^2 = 294 \\
\Leftrightarrow x^2 = \frac{294}{6}=49 \\
\Leftrightarrow x = 7 \vee x = -7 \\
V = \Big\{-7, 7 \Big\} \\ -----------------\)
- \(-6x^2+54=0 \\
\Leftrightarrow -6x^2 = -54 \\
\Leftrightarrow x^2 = \frac{-54}{-6}=9 \\
\Leftrightarrow x = 3 \vee x = -3 \\
V = \Big\{-3, 3 \Big\} \\ -----------------\)
- \(-9x^2+121=-4x^2-4 \\ \Leftrightarrow -9x^2+4x^2=-4-121 \\
\Leftrightarrow -5x^2 = -125 \\
\Leftrightarrow x^2 = \frac{-125}{-5}=25 \\
\Leftrightarrow x = 5 \vee x = -5 \\
V = \Big\{-5, 5 \Big\} \\ -----------------\)