Los de vierkantsvergelijking op zonder de discriminant te gebruiken
- \(3(-4x^2-3)=-(4x^2+657)\)
- \(6x^2+216=0\)
- \(-11x^2+251=-8x^2+8\)
- \(-8x^2+8=0\)
- \(9x^2+13=5x^2-3\)
- \(-4x^2+0=0\)
- \(-2(4x^2-5)=-(x^2+1362)\)
- \(2(-7x^2-6)=-(11x^2+375)\)
- \(-4(-10x^2+5)=-(-46x^2+44)\)
- \(4(-10x^2-2)=-(38x^2+136)\)
- \(-3x^2+27=0\)
- \(9x^2-91=5x^2+9\)
Los de vierkantsvergelijking op zonder de discriminant te gebruiken
Verbetersleutel
- \(3(-4x^2-3)=-(4x^2+657) \\ \Leftrightarrow -12x^2-9=-4x^2-657 \\
\Leftrightarrow -12x^2+4x^2=-657+9 \\
\Leftrightarrow -8x^2 = -648 \\
\Leftrightarrow x^2 = \frac{-648}{-8}=81 \\
\Leftrightarrow x = 9 \vee x = -9 \\
V = \Big\{-9, 9 \Big\} \\ -----------------\)
- \(6x^2+216=0 \\
\Leftrightarrow 6x^2 = -216 \\
\Leftrightarrow x^2 = \frac{-216}{6} < 0 \\
V = \varnothing \\ -----------------\)
- \(-11x^2+251=-8x^2+8 \\ \Leftrightarrow -11x^2+8x^2=8-251 \\
\Leftrightarrow -3x^2 = -243 \\
\Leftrightarrow x^2 = \frac{-243}{-3}=81 \\
\Leftrightarrow x = 9 \vee x = -9 \\
V = \Big\{-9, 9 \Big\} \\ -----------------\)
- \(-8x^2+8=0 \\
\Leftrightarrow -8x^2 = -8 \\
\Leftrightarrow x^2 = \frac{-8}{-8}=1 \\
\Leftrightarrow x = 1 \vee x = -1 \\
V = \Big\{-1, 1 \Big\} \\ -----------------\)
- \(9x^2+13=5x^2-3 \\ \Leftrightarrow 9x^2-5x^2=-3-13 \\
\Leftrightarrow 4x^2 = -16 \\
\Leftrightarrow x^2 = \frac{-16}{4} < 0 \\
V = \varnothing \\ -----------------\)
- \(-4x^2+0=0 \\
\Leftrightarrow -4x^2 = 0 \\
\Leftrightarrow x^2 = \frac{0}{-4}\\
\Leftrightarrow x = 0 \\
V = \Big\{ 0 \Big\} \\ -----------------\)
- \(-2(4x^2-5)=-(x^2+1362) \\ \Leftrightarrow -8x^2+10=-x^2-1362 \\
\Leftrightarrow -8x^2+x^2=-1362-10 \\
\Leftrightarrow -7x^2 = -1372 \\
\Leftrightarrow x^2 = \frac{-1372}{-7}=196 \\
\Leftrightarrow x = 14 \vee x = -14 \\
V = \Big\{-14, 14 \Big\} \\ -----------------\)
- \(2(-7x^2-6)=-(11x^2+375) \\ \Leftrightarrow -14x^2-12=-11x^2-375 \\
\Leftrightarrow -14x^2+11x^2=-375+12 \\
\Leftrightarrow -3x^2 = -363 \\
\Leftrightarrow x^2 = \frac{-363}{-3}=121 \\
\Leftrightarrow x = 11 \vee x = -11 \\
V = \Big\{-11, 11 \Big\} \\ -----------------\)
- \(-4(-10x^2+5)=-(-46x^2+44) \\ \Leftrightarrow 40x^2-20=46x^2-44 \\
\Leftrightarrow 40x^2-46x^2=-44+20 \\
\Leftrightarrow -6x^2 = -24 \\
\Leftrightarrow x^2 = \frac{-24}{-6}=4 \\
\Leftrightarrow x = 2 \vee x = -2 \\
V = \Big\{-2, 2 \Big\} \\ -----------------\)
- \(4(-10x^2-2)=-(38x^2+136) \\ \Leftrightarrow -40x^2-8=-38x^2-136 \\
\Leftrightarrow -40x^2+38x^2=-136+8 \\
\Leftrightarrow -2x^2 = -128 \\
\Leftrightarrow x^2 = \frac{-128}{-2}=64 \\
\Leftrightarrow x = 8 \vee x = -8 \\
V = \Big\{-8, 8 \Big\} \\ -----------------\)
- \(-3x^2+27=0 \\
\Leftrightarrow -3x^2 = -27 \\
\Leftrightarrow x^2 = \frac{-27}{-3}=9 \\
\Leftrightarrow x = 3 \vee x = -3 \\
V = \Big\{-3, 3 \Big\} \\ -----------------\)
- \(9x^2-91=5x^2+9 \\ \Leftrightarrow 9x^2-5x^2=9+91 \\
\Leftrightarrow 4x^2 = 100 \\
\Leftrightarrow x^2 = \frac{100}{4}=25 \\
\Leftrightarrow x = 5 \vee x = -5 \\
V = \Big\{-5, 5 \Big\} \\ -----------------\)