Los de vierkantsvergelijking op zonder de discriminant te gebruiken
- \(-4x^2-7=-8x^2-3\)
- \(-3(-10x^2+6)=-(-22x^2-54)\)
- \(3x^2+3=0\)
- \(5(-8x^2-9)=-(33x^2-522)\)
- \(-7x^2-41=-8x^2+8\)
- \(x^2+25=0\)
- \(3(-9x^2-4)=-(22x^2-233)\)
- \(3x^2+51=2x^2+2\)
- \(5x^2-405=0\)
- \(5x^2-1125=0\)
- \(-4x^2+676=0\)
- \(-4x^2-484=0\)
Los de vierkantsvergelijking op zonder de discriminant te gebruiken
Verbetersleutel
- \(-4x^2-7=-8x^2-3 \\ \Leftrightarrow -4x^2+8x^2=-3+7 \\
\Leftrightarrow 4x^2 = 4 \\
\Leftrightarrow x^2 = \frac{4}{4}=1 \\
\Leftrightarrow x = 1 \vee x = -1 \\
V = \Big\{-1, 1 \Big\} \\ -----------------\)
- \(-3(-10x^2+6)=-(-22x^2-54) \\ \Leftrightarrow 30x^2-18=22x^2+54 \\
\Leftrightarrow 30x^2-22x^2=54+18 \\
\Leftrightarrow 8x^2 = 72 \\
\Leftrightarrow x^2 = \frac{72}{8}=9 \\
\Leftrightarrow x = 3 \vee x = -3 \\
V = \Big\{-3, 3 \Big\} \\ -----------------\)
- \(3x^2+3=0 \\
\Leftrightarrow 3x^2 = -3 \\
\Leftrightarrow x^2 = \frac{-3}{3} < 0 \\
V = \varnothing \\ -----------------\)
- \(5(-8x^2-9)=-(33x^2-522) \\ \Leftrightarrow -40x^2-45=-33x^2+522 \\
\Leftrightarrow -40x^2+33x^2=522+45 \\
\Leftrightarrow -7x^2 = 567 \\
\Leftrightarrow x^2 = \frac{567}{-7} < 0 \\
V = \varnothing \\ -----------------\)
- \(-7x^2-41=-8x^2+8 \\ \Leftrightarrow -7x^2+8x^2=8+41 \\
\Leftrightarrow x^2 = 49 \\
\Leftrightarrow x^2 = \frac{49}{1}=49 \\
\Leftrightarrow x = 7 \vee x = -7 \\
V = \Big\{-7, 7 \Big\} \\ -----------------\)
- \(x^2+25=0 \\
\Leftrightarrow x^2 = -25 \\
\Leftrightarrow x^2 = \frac{-25}{1} < 0 \\
V = \varnothing \\ -----------------\)
- \(3(-9x^2-4)=-(22x^2-233) \\ \Leftrightarrow -27x^2-12=-22x^2+233 \\
\Leftrightarrow -27x^2+22x^2=233+12 \\
\Leftrightarrow -5x^2 = 245 \\
\Leftrightarrow x^2 = \frac{245}{-5} < 0 \\
V = \varnothing \\ -----------------\)
- \(3x^2+51=2x^2+2 \\ \Leftrightarrow 3x^2-2x^2=2-51 \\
\Leftrightarrow x^2 = -49 \\
\Leftrightarrow x^2 = \frac{-49}{1} < 0 \\
V = \varnothing \\ -----------------\)
- \(5x^2-405=0 \\
\Leftrightarrow 5x^2 = 405 \\
\Leftrightarrow x^2 = \frac{405}{5}=81 \\
\Leftrightarrow x = 9 \vee x = -9 \\
V = \Big\{-9, 9 \Big\} \\ -----------------\)
- \(5x^2-1125=0 \\
\Leftrightarrow 5x^2 = 1125 \\
\Leftrightarrow x^2 = \frac{1125}{5}=225 \\
\Leftrightarrow x = 15 \vee x = -15 \\
V = \Big\{-15, 15 \Big\} \\ -----------------\)
- \(-4x^2+676=0 \\
\Leftrightarrow -4x^2 = -676 \\
\Leftrightarrow x^2 = \frac{-676}{-4}=169 \\
\Leftrightarrow x = 13 \vee x = -13 \\
V = \Big\{-13, 13 \Big\} \\ -----------------\)
- \(-4x^2-484=0 \\
\Leftrightarrow -4x^2 = 484 \\
\Leftrightarrow x^2 = \frac{484}{-4} < 0 \\
V = \varnothing \\ -----------------\)