Los de vierkantsvergelijking op zonder de discriminant te gebruiken
- \(x^2-16=0\)
- \(-2(2x^2-10)=-(x^2-167)\)
- \(-15x^2-1146=-7x^2+6\)
- \(-4(3x^2+7)=-(6x^2+1378)\)
- \(-17x^2-134=-9x^2-6\)
- \(7x^2-1575=0\)
- \(2(10x^2-7)=-(-27x^2+1197)\)
- \(-4x^2+36=0\)
- \(-3x^2+675=0\)
- \(-2x^2+2=-8x^2+2\)
- \(x^2-247=-3x^2+9\)
- \(-18x^2-63=-10x^2+9\)
Los de vierkantsvergelijking op zonder de discriminant te gebruiken
Verbetersleutel
- \(x^2-16=0 \\
\Leftrightarrow x^2 = 16 \\
\Leftrightarrow x^2 = \frac{16}{1}=16 \\
\Leftrightarrow x = 4 \vee x = -4 \\
V = \Big\{-4, 4 \Big\} \\ -----------------\)
- \(-2(2x^2-10)=-(x^2-167) \\ \Leftrightarrow -4x^2+20=-x^2+167 \\
\Leftrightarrow -4x^2+x^2=167-20 \\
\Leftrightarrow -3x^2 = 147 \\
\Leftrightarrow x^2 = \frac{147}{-3} < 0 \\
V = \varnothing \\ -----------------\)
- \(-15x^2-1146=-7x^2+6 \\ \Leftrightarrow -15x^2+7x^2=6+1146 \\
\Leftrightarrow -8x^2 = 1152 \\
\Leftrightarrow x^2 = \frac{1152}{-8} < 0 \\
V = \varnothing \\ -----------------\)
- \(-4(3x^2+7)=-(6x^2+1378) \\ \Leftrightarrow -12x^2-28=-6x^2-1378 \\
\Leftrightarrow -12x^2+6x^2=-1378+28 \\
\Leftrightarrow -6x^2 = -1350 \\
\Leftrightarrow x^2 = \frac{-1350}{-6}=225 \\
\Leftrightarrow x = 15 \vee x = -15 \\
V = \Big\{-15, 15 \Big\} \\ -----------------\)
- \(-17x^2-134=-9x^2-6 \\ \Leftrightarrow -17x^2+9x^2=-6+134 \\
\Leftrightarrow -8x^2 = 128 \\
\Leftrightarrow x^2 = \frac{128}{-8} < 0 \\
V = \varnothing \\ -----------------\)
- \(7x^2-1575=0 \\
\Leftrightarrow 7x^2 = 1575 \\
\Leftrightarrow x^2 = \frac{1575}{7}=225 \\
\Leftrightarrow x = 15 \vee x = -15 \\
V = \Big\{-15, 15 \Big\} \\ -----------------\)
- \(2(10x^2-7)=-(-27x^2+1197) \\ \Leftrightarrow 20x^2-14=27x^2-1197 \\
\Leftrightarrow 20x^2-27x^2=-1197+14 \\
\Leftrightarrow -7x^2 = -1183 \\
\Leftrightarrow x^2 = \frac{-1183}{-7}=169 \\
\Leftrightarrow x = 13 \vee x = -13 \\
V = \Big\{-13, 13 \Big\} \\ -----------------\)
- \(-4x^2+36=0 \\
\Leftrightarrow -4x^2 = -36 \\
\Leftrightarrow x^2 = \frac{-36}{-4}=9 \\
\Leftrightarrow x = 3 \vee x = -3 \\
V = \Big\{-3, 3 \Big\} \\ -----------------\)
- \(-3x^2+675=0 \\
\Leftrightarrow -3x^2 = -675 \\
\Leftrightarrow x^2 = \frac{-675}{-3}=225 \\
\Leftrightarrow x = 15 \vee x = -15 \\
V = \Big\{-15, 15 \Big\} \\ -----------------\)
- \(-2x^2+2=-8x^2+2 \\ \Leftrightarrow -2x^2+8x^2=2-2 \\
\Leftrightarrow 6x^2 = 0 \\
\Leftrightarrow x^2 = \frac{0}{6}\\
\Leftrightarrow x = 0 \\
V = \Big\{ 0 \Big\} \\ -----------------\)
- \(x^2-247=-3x^2+9 \\ \Leftrightarrow x^2+3x^2=9+247 \\
\Leftrightarrow 4x^2 = 256 \\
\Leftrightarrow x^2 = \frac{256}{4}=64 \\
\Leftrightarrow x = 8 \vee x = -8 \\
V = \Big\{-8, 8 \Big\} \\ -----------------\)
- \(-18x^2-63=-10x^2+9 \\ \Leftrightarrow -18x^2+10x^2=9+63 \\
\Leftrightarrow -8x^2 = 72 \\
\Leftrightarrow x^2 = \frac{72}{-8} < 0 \\
V = \varnothing \\ -----------------\)