Los de vierkantsvergelijking op zonder de discriminant te gebruiken
- \(6x^2+384=0\)
- \(5x^2-180=0\)
- \(-6x^2-66=-10x^2-2\)
- \(-2(-2x^2-10)=-(3x^2+8)\)
- \(-x^2+100=0\)
- \(15x^2-394=7x^2-2\)
- \(4(-3x^2-7)=-(14x^2-422)\)
- \(-3(-6x^2-5)=-(-14x^2-799)\)
- \(5(8x^2-7)=-(-41x^2+60)\)
- \(14x^2-51=8x^2+3\)
- \(-3(4x^2-2)=-(18x^2+858)\)
- \(11x^2+720=5x^2-6\)
Los de vierkantsvergelijking op zonder de discriminant te gebruiken
Verbetersleutel
- \(6x^2+384=0 \\
\Leftrightarrow 6x^2 = -384 \\
\Leftrightarrow x^2 = \frac{-384}{6} < 0 \\
V = \varnothing \\ -----------------\)
- \(5x^2-180=0 \\
\Leftrightarrow 5x^2 = 180 \\
\Leftrightarrow x^2 = \frac{180}{5}=36 \\
\Leftrightarrow x = 6 \vee x = -6 \\
V = \Big\{-6, 6 \Big\} \\ -----------------\)
- \(-6x^2-66=-10x^2-2 \\ \Leftrightarrow -6x^2+10x^2=-2+66 \\
\Leftrightarrow 4x^2 = 64 \\
\Leftrightarrow x^2 = \frac{64}{4}=16 \\
\Leftrightarrow x = 4 \vee x = -4 \\
V = \Big\{-4, 4 \Big\} \\ -----------------\)
- \(-2(-2x^2-10)=-(3x^2+8) \\ \Leftrightarrow 4x^2+20=-3x^2-8 \\
\Leftrightarrow 4x^2+3x^2=-8-20 \\
\Leftrightarrow 7x^2 = -28 \\
\Leftrightarrow x^2 = \frac{-28}{7} < 0 \\
V = \varnothing \\ -----------------\)
- \(-x^2+100=0 \\
\Leftrightarrow -x^2 = -100 \\
\Leftrightarrow x^2 = \frac{-100}{-1}=100 \\
\Leftrightarrow x = 10 \vee x = -10 \\
V = \Big\{-10, 10 \Big\} \\ -----------------\)
- \(15x^2-394=7x^2-2 \\ \Leftrightarrow 15x^2-7x^2=-2+394 \\
\Leftrightarrow 8x^2 = 392 \\
\Leftrightarrow x^2 = \frac{392}{8}=49 \\
\Leftrightarrow x = 7 \vee x = -7 \\
V = \Big\{-7, 7 \Big\} \\ -----------------\)
- \(4(-3x^2-7)=-(14x^2-422) \\ \Leftrightarrow -12x^2-28=-14x^2+422 \\
\Leftrightarrow -12x^2+14x^2=422+28 \\
\Leftrightarrow 2x^2 = 450 \\
\Leftrightarrow x^2 = \frac{450}{2}=225 \\
\Leftrightarrow x = 15 \vee x = -15 \\
V = \Big\{-15, 15 \Big\} \\ -----------------\)
- \(-3(-6x^2-5)=-(-14x^2-799) \\ \Leftrightarrow 18x^2+15=14x^2+799 \\
\Leftrightarrow 18x^2-14x^2=799-15 \\
\Leftrightarrow 4x^2 = 784 \\
\Leftrightarrow x^2 = \frac{784}{4}=196 \\
\Leftrightarrow x = 14 \vee x = -14 \\
V = \Big\{-14, 14 \Big\} \\ -----------------\)
- \(5(8x^2-7)=-(-41x^2+60) \\ \Leftrightarrow 40x^2-35=41x^2-60 \\
\Leftrightarrow 40x^2-41x^2=-60+35 \\
\Leftrightarrow -x^2 = -25 \\
\Leftrightarrow x^2 = \frac{-25}{-1}=25 \\
\Leftrightarrow x = 5 \vee x = -5 \\
V = \Big\{-5, 5 \Big\} \\ -----------------\)
- \(14x^2-51=8x^2+3 \\ \Leftrightarrow 14x^2-8x^2=3+51 \\
\Leftrightarrow 6x^2 = 54 \\
\Leftrightarrow x^2 = \frac{54}{6}=9 \\
\Leftrightarrow x = 3 \vee x = -3 \\
V = \Big\{-3, 3 \Big\} \\ -----------------\)
- \(-3(4x^2-2)=-(18x^2+858) \\ \Leftrightarrow -12x^2+6=-18x^2-858 \\
\Leftrightarrow -12x^2+18x^2=-858-6 \\
\Leftrightarrow 6x^2 = -864 \\
\Leftrightarrow x^2 = \frac{-864}{6} < 0 \\
V = \varnothing \\ -----------------\)
- \(11x^2+720=5x^2-6 \\ \Leftrightarrow 11x^2-5x^2=-6-720 \\
\Leftrightarrow 6x^2 = -726 \\
\Leftrightarrow x^2 = \frac{-726}{6} < 0 \\
V = \varnothing \\ -----------------\)