Los de vierkantsvergelijking op zonder de discriminant te gebruiken
- \(-4(-6x^2-4)=-(-32x^2+1136)\)
- \(-4(-2x^2-2)=-(-11x^2+19)\)
- \(-2(9x^2-10)=-(16x^2-20)\)
- \(-4x^2+256=0\)
- \(-7x^2-1183=0\)
- \(-3x^2-615=-8x^2-10\)
- \(-15x^2-7=-8x^2-7\)
- \(9x^2+47=8x^2-2\)
- \(-2x^2+242=0\)
- \(-3(-7x^2+3)=-(-19x^2-23)\)
- \(-5x^2+0=0\)
- \(-3(-7x^2+8)=-(-27x^2-1152)\)
Los de vierkantsvergelijking op zonder de discriminant te gebruiken
Verbetersleutel
- \(-4(-6x^2-4)=-(-32x^2+1136) \\ \Leftrightarrow 24x^2+16=32x^2-1136 \\
\Leftrightarrow 24x^2-32x^2=-1136-16 \\
\Leftrightarrow -8x^2 = -1152 \\
\Leftrightarrow x^2 = \frac{-1152}{-8}=144 \\
\Leftrightarrow x = 12 \vee x = -12 \\
V = \Big\{-12, 12 \Big\} \\ -----------------\)
- \(-4(-2x^2-2)=-(-11x^2+19) \\ \Leftrightarrow 8x^2+8=11x^2-19 \\
\Leftrightarrow 8x^2-11x^2=-19-8 \\
\Leftrightarrow -3x^2 = -27 \\
\Leftrightarrow x^2 = \frac{-27}{-3}=9 \\
\Leftrightarrow x = 3 \vee x = -3 \\
V = \Big\{-3, 3 \Big\} \\ -----------------\)
- \(-2(9x^2-10)=-(16x^2-20) \\ \Leftrightarrow -18x^2+20=-16x^2+20 \\
\Leftrightarrow -18x^2+16x^2=20-20 \\
\Leftrightarrow -2x^2 = 0 \\
\Leftrightarrow x^2 = \frac{0}{-2}\\
\Leftrightarrow x = 0 \\
V = \Big\{ 0 \Big\} \\ -----------------\)
- \(-4x^2+256=0 \\
\Leftrightarrow -4x^2 = -256 \\
\Leftrightarrow x^2 = \frac{-256}{-4}=64 \\
\Leftrightarrow x = 8 \vee x = -8 \\
V = \Big\{-8, 8 \Big\} \\ -----------------\)
- \(-7x^2-1183=0 \\
\Leftrightarrow -7x^2 = 1183 \\
\Leftrightarrow x^2 = \frac{1183}{-7} < 0 \\
V = \varnothing \\ -----------------\)
- \(-3x^2-615=-8x^2-10 \\ \Leftrightarrow -3x^2+8x^2=-10+615 \\
\Leftrightarrow 5x^2 = 605 \\
\Leftrightarrow x^2 = \frac{605}{5}=121 \\
\Leftrightarrow x = 11 \vee x = -11 \\
V = \Big\{-11, 11 \Big\} \\ -----------------\)
- \(-15x^2-7=-8x^2-7 \\ \Leftrightarrow -15x^2+8x^2=-7+7 \\
\Leftrightarrow -7x^2 = 0 \\
\Leftrightarrow x^2 = \frac{0}{-7}\\
\Leftrightarrow x = 0 \\
V = \Big\{ 0 \Big\} \\ -----------------\)
- \(9x^2+47=8x^2-2 \\ \Leftrightarrow 9x^2-8x^2=-2-47 \\
\Leftrightarrow x^2 = -49 \\
\Leftrightarrow x^2 = \frac{-49}{1} < 0 \\
V = \varnothing \\ -----------------\)
- \(-2x^2+242=0 \\
\Leftrightarrow -2x^2 = -242 \\
\Leftrightarrow x^2 = \frac{-242}{-2}=121 \\
\Leftrightarrow x = 11 \vee x = -11 \\
V = \Big\{-11, 11 \Big\} \\ -----------------\)
- \(-3(-7x^2+3)=-(-19x^2-23) \\ \Leftrightarrow 21x^2-9=19x^2+23 \\
\Leftrightarrow 21x^2-19x^2=23+9 \\
\Leftrightarrow 2x^2 = 32 \\
\Leftrightarrow x^2 = \frac{32}{2}=16 \\
\Leftrightarrow x = 4 \vee x = -4 \\
V = \Big\{-4, 4 \Big\} \\ -----------------\)
- \(-5x^2+0=0 \\
\Leftrightarrow -5x^2 = 0 \\
\Leftrightarrow x^2 = \frac{0}{-5}\\
\Leftrightarrow x = 0 \\
V = \Big\{ 0 \Big\} \\ -----------------\)
- \(-3(-7x^2+8)=-(-27x^2-1152) \\ \Leftrightarrow 21x^2-24=27x^2+1152 \\
\Leftrightarrow 21x^2-27x^2=1152+24 \\
\Leftrightarrow -6x^2 = 1176 \\
\Leftrightarrow x^2 = \frac{1176}{-6} < 0 \\
V = \varnothing \\ -----------------\)