Los de vierkantsvergelijking op zonder de discriminant te gebruiken
- \(-2x^2+70=-3x^2+6\)
- \(-7x^2-6=-8x^2-6\)
- \(-7x^2+7=0\)
- \(3(-8x^2-6)=-(23x^2+18)\)
- \(-3x^2+300=0\)
- \(4x^2-64=0\)
- \(-13x^2+365=-10x^2+2\)
- \(7x^2+0=0\)
- \(-5x^2-80=0\)
- \(-4x^2-316=-9x^2+4\)
- \(-13x^2+41=-8x^2-4\)
- \(-3(9x^2+5)=-(20x^2+862)\)
Los de vierkantsvergelijking op zonder de discriminant te gebruiken
Verbetersleutel
- \(-2x^2+70=-3x^2+6 \\ \Leftrightarrow -2x^2+3x^2=6-70 \\
\Leftrightarrow x^2 = -64 \\
\Leftrightarrow x^2 = \frac{-64}{1} < 0 \\
V = \varnothing \\ -----------------\)
- \(-7x^2-6=-8x^2-6 \\ \Leftrightarrow -7x^2+8x^2=-6+6 \\
\Leftrightarrow x^2 = 0 \\
\Leftrightarrow x^2 = \frac{0}{1}\\
\Leftrightarrow x = 0 \\
V = \Big\{ 0 \Big\} \\ -----------------\)
- \(-7x^2+7=0 \\
\Leftrightarrow -7x^2 = -7 \\
\Leftrightarrow x^2 = \frac{-7}{-7}=1 \\
\Leftrightarrow x = 1 \vee x = -1 \\
V = \Big\{-1, 1 \Big\} \\ -----------------\)
- \(3(-8x^2-6)=-(23x^2+18) \\ \Leftrightarrow -24x^2-18=-23x^2-18 \\
\Leftrightarrow -24x^2+23x^2=-18+18 \\
\Leftrightarrow -x^2 = 0 \\
\Leftrightarrow x^2 = \frac{0}{-1}\\
\Leftrightarrow x = 0 \\
V = \Big\{ 0 \Big\} \\ -----------------\)
- \(-3x^2+300=0 \\
\Leftrightarrow -3x^2 = -300 \\
\Leftrightarrow x^2 = \frac{-300}{-3}=100 \\
\Leftrightarrow x = 10 \vee x = -10 \\
V = \Big\{-10, 10 \Big\} \\ -----------------\)
- \(4x^2-64=0 \\
\Leftrightarrow 4x^2 = 64 \\
\Leftrightarrow x^2 = \frac{64}{4}=16 \\
\Leftrightarrow x = 4 \vee x = -4 \\
V = \Big\{-4, 4 \Big\} \\ -----------------\)
- \(-13x^2+365=-10x^2+2 \\ \Leftrightarrow -13x^2+10x^2=2-365 \\
\Leftrightarrow -3x^2 = -363 \\
\Leftrightarrow x^2 = \frac{-363}{-3}=121 \\
\Leftrightarrow x = 11 \vee x = -11 \\
V = \Big\{-11, 11 \Big\} \\ -----------------\)
- \(7x^2+0=0 \\
\Leftrightarrow 7x^2 = 0 \\
\Leftrightarrow x^2 = \frac{0}{7}\\
\Leftrightarrow x = 0 \\
V = \Big\{ 0 \Big\} \\ -----------------\)
- \(-5x^2-80=0 \\
\Leftrightarrow -5x^2 = 80 \\
\Leftrightarrow x^2 = \frac{80}{-5} < 0 \\
V = \varnothing \\ -----------------\)
- \(-4x^2-316=-9x^2+4 \\ \Leftrightarrow -4x^2+9x^2=4+316 \\
\Leftrightarrow 5x^2 = 320 \\
\Leftrightarrow x^2 = \frac{320}{5}=64 \\
\Leftrightarrow x = 8 \vee x = -8 \\
V = \Big\{-8, 8 \Big\} \\ -----------------\)
- \(-13x^2+41=-8x^2-4 \\ \Leftrightarrow -13x^2+8x^2=-4-41 \\
\Leftrightarrow -5x^2 = -45 \\
\Leftrightarrow x^2 = \frac{-45}{-5}=9 \\
\Leftrightarrow x = 3 \vee x = -3 \\
V = \Big\{-3, 3 \Big\} \\ -----------------\)
- \(-3(9x^2+5)=-(20x^2+862) \\ \Leftrightarrow -27x^2-15=-20x^2-862 \\
\Leftrightarrow -27x^2+20x^2=-862+15 \\
\Leftrightarrow -7x^2 = -847 \\
\Leftrightarrow x^2 = \frac{-847}{-7}=121 \\
\Leftrightarrow x = 11 \vee x = -11 \\
V = \Big\{-11, 11 \Big\} \\ -----------------\)