Los de vierkantsvergelijking op zonder de discriminant te gebruiken
- \(-2(-2x^2+8)=-(0x^2-768)\)
- \(2(-6x^2+8)=-(20x^2+1136)\)
- \(-9x^2-43=-8x^2-7\)
- \(5(-7x^2+6)=-(36x^2-174)\)
- \(x^2-102=-5x^2-6\)
- \(8x^2+1352=0\)
- \(7x^2-113=10x^2-5\)
- \(-x^2-31=5x^2-7\)
- \(3(4x^2+6)=-(-19x^2+990)\)
- \(4x^2-58=10x^2-4\)
- \(-4x^2-676=0\)
- \(2x^2-18=0\)
Los de vierkantsvergelijking op zonder de discriminant te gebruiken
Verbetersleutel
- \(-2(-2x^2+8)=-(0x^2-768) \\ \Leftrightarrow 4x^2-16=0x^2+768 \\
\Leftrightarrow 4x^2+0x^2=768+16 \\
\Leftrightarrow 4x^2 = 784 \\
\Leftrightarrow x^2 = \frac{784}{4}=196 \\
\Leftrightarrow x = 14 \vee x = -14 \\
V = \Big\{-14, 14 \Big\} \\ -----------------\)
- \(2(-6x^2+8)=-(20x^2+1136) \\ \Leftrightarrow -12x^2+16=-20x^2-1136 \\
\Leftrightarrow -12x^2+20x^2=-1136-16 \\
\Leftrightarrow 8x^2 = -1152 \\
\Leftrightarrow x^2 = \frac{-1152}{8} < 0 \\
V = \varnothing \\ -----------------\)
- \(-9x^2-43=-8x^2-7 \\ \Leftrightarrow -9x^2+8x^2=-7+43 \\
\Leftrightarrow -x^2 = 36 \\
\Leftrightarrow x^2 = \frac{36}{-1} < 0 \\
V = \varnothing \\ -----------------\)
- \(5(-7x^2+6)=-(36x^2-174) \\ \Leftrightarrow -35x^2+30=-36x^2+174 \\
\Leftrightarrow -35x^2+36x^2=174-30 \\
\Leftrightarrow x^2 = 144 \\
\Leftrightarrow x^2 = \frac{144}{1}=144 \\
\Leftrightarrow x = 12 \vee x = -12 \\
V = \Big\{-12, 12 \Big\} \\ -----------------\)
- \(x^2-102=-5x^2-6 \\ \Leftrightarrow x^2+5x^2=-6+102 \\
\Leftrightarrow 6x^2 = 96 \\
\Leftrightarrow x^2 = \frac{96}{6}=16 \\
\Leftrightarrow x = 4 \vee x = -4 \\
V = \Big\{-4, 4 \Big\} \\ -----------------\)
- \(8x^2+1352=0 \\
\Leftrightarrow 8x^2 = -1352 \\
\Leftrightarrow x^2 = \frac{-1352}{8} < 0 \\
V = \varnothing \\ -----------------\)
- \(7x^2-113=10x^2-5 \\ \Leftrightarrow 7x^2-10x^2=-5+113 \\
\Leftrightarrow -3x^2 = 108 \\
\Leftrightarrow x^2 = \frac{108}{-3} < 0 \\
V = \varnothing \\ -----------------\)
- \(-x^2-31=5x^2-7 \\ \Leftrightarrow -x^2-5x^2=-7+31 \\
\Leftrightarrow -6x^2 = 24 \\
\Leftrightarrow x^2 = \frac{24}{-6} < 0 \\
V = \varnothing \\ -----------------\)
- \(3(4x^2+6)=-(-19x^2+990) \\ \Leftrightarrow 12x^2+18=19x^2-990 \\
\Leftrightarrow 12x^2-19x^2=-990-18 \\
\Leftrightarrow -7x^2 = -1008 \\
\Leftrightarrow x^2 = \frac{-1008}{-7}=144 \\
\Leftrightarrow x = 12 \vee x = -12 \\
V = \Big\{-12, 12 \Big\} \\ -----------------\)
- \(4x^2-58=10x^2-4 \\ \Leftrightarrow 4x^2-10x^2=-4+58 \\
\Leftrightarrow -6x^2 = 54 \\
\Leftrightarrow x^2 = \frac{54}{-6} < 0 \\
V = \varnothing \\ -----------------\)
- \(-4x^2-676=0 \\
\Leftrightarrow -4x^2 = 676 \\
\Leftrightarrow x^2 = \frac{676}{-4} < 0 \\
V = \varnothing \\ -----------------\)
- \(2x^2-18=0 \\
\Leftrightarrow 2x^2 = 18 \\
\Leftrightarrow x^2 = \frac{18}{2}=9 \\
\Leftrightarrow x = 3 \vee x = -3 \\
V = \Big\{-3, 3 \Big\} \\ -----------------\)