Los de vierkantsvergelijking op zonder de discriminant te gebruiken
- \(-8x^2-32=0\)
- \(-5x^2+5=0\)
- \(9x^2-20=10x^2-4\)
- \(-3x^2-43=-7x^2-7\)
- \(3(6x^2+10)=-(-17x^2-111)\)
- \(-x^2+9=0\)
- \(2x^2-64=-6x^2+8\)
- \(-2x^2+128=0\)
- \(3x^2+0=0\)
- \(12x^2-504=4x^2+8\)
- \(5(-8x^2+8)=-(34x^2-526)\)
- \(5(7x^2-6)=-(-34x^2+30)\)
Los de vierkantsvergelijking op zonder de discriminant te gebruiken
Verbetersleutel
- \(-8x^2-32=0 \\
\Leftrightarrow -8x^2 = 32 \\
\Leftrightarrow x^2 = \frac{32}{-8} < 0 \\
V = \varnothing \\ -----------------\)
- \(-5x^2+5=0 \\
\Leftrightarrow -5x^2 = -5 \\
\Leftrightarrow x^2 = \frac{-5}{-5}=1 \\
\Leftrightarrow x = 1 \vee x = -1 \\
V = \Big\{-1, 1 \Big\} \\ -----------------\)
- \(9x^2-20=10x^2-4 \\ \Leftrightarrow 9x^2-10x^2=-4+20 \\
\Leftrightarrow -x^2 = 16 \\
\Leftrightarrow x^2 = \frac{16}{-1} < 0 \\
V = \varnothing \\ -----------------\)
- \(-3x^2-43=-7x^2-7 \\ \Leftrightarrow -3x^2+7x^2=-7+43 \\
\Leftrightarrow 4x^2 = 36 \\
\Leftrightarrow x^2 = \frac{36}{4}=9 \\
\Leftrightarrow x = 3 \vee x = -3 \\
V = \Big\{-3, 3 \Big\} \\ -----------------\)
- \(3(6x^2+10)=-(-17x^2-111) \\ \Leftrightarrow 18x^2+30=17x^2+111 \\
\Leftrightarrow 18x^2-17x^2=111-30 \\
\Leftrightarrow x^2 = 81 \\
\Leftrightarrow x^2 = \frac{81}{1}=81 \\
\Leftrightarrow x = 9 \vee x = -9 \\
V = \Big\{-9, 9 \Big\} \\ -----------------\)
- \(-x^2+9=0 \\
\Leftrightarrow -x^2 = -9 \\
\Leftrightarrow x^2 = \frac{-9}{-1}=9 \\
\Leftrightarrow x = 3 \vee x = -3 \\
V = \Big\{-3, 3 \Big\} \\ -----------------\)
- \(2x^2-64=-6x^2+8 \\ \Leftrightarrow 2x^2+6x^2=8+64 \\
\Leftrightarrow 8x^2 = 72 \\
\Leftrightarrow x^2 = \frac{72}{8}=9 \\
\Leftrightarrow x = 3 \vee x = -3 \\
V = \Big\{-3, 3 \Big\} \\ -----------------\)
- \(-2x^2+128=0 \\
\Leftrightarrow -2x^2 = -128 \\
\Leftrightarrow x^2 = \frac{-128}{-2}=64 \\
\Leftrightarrow x = 8 \vee x = -8 \\
V = \Big\{-8, 8 \Big\} \\ -----------------\)
- \(3x^2+0=0 \\
\Leftrightarrow 3x^2 = 0 \\
\Leftrightarrow x^2 = \frac{0}{3}\\
\Leftrightarrow x = 0 \\
V = \Big\{ 0 \Big\} \\ -----------------\)
- \(12x^2-504=4x^2+8 \\ \Leftrightarrow 12x^2-4x^2=8+504 \\
\Leftrightarrow 8x^2 = 512 \\
\Leftrightarrow x^2 = \frac{512}{8}=64 \\
\Leftrightarrow x = 8 \vee x = -8 \\
V = \Big\{-8, 8 \Big\} \\ -----------------\)
- \(5(-8x^2+8)=-(34x^2-526) \\ \Leftrightarrow -40x^2+40=-34x^2+526 \\
\Leftrightarrow -40x^2+34x^2=526-40 \\
\Leftrightarrow -6x^2 = 486 \\
\Leftrightarrow x^2 = \frac{486}{-6} < 0 \\
V = \varnothing \\ -----------------\)
- \(5(7x^2-6)=-(-34x^2+30) \\ \Leftrightarrow 35x^2-30=34x^2-30 \\
\Leftrightarrow 35x^2-34x^2=-30+30 \\
\Leftrightarrow x^2 = 0 \\
\Leftrightarrow x^2 = \frac{0}{1}\\
\Leftrightarrow x = 0 \\
V = \Big\{ 0 \Big\} \\ -----------------\)