Los de vierkantsvergelijking op zonder de discriminant te gebruiken
- \(4x^2+0=0\)
- \(3x^2-7=8x^2-7\)
- \(6x^2+864=0\)
- \(-2(-4x^2-5)=-(-11x^2-310)\)
- \(-x^2-399=4x^2+6\)
- \(3(-9x^2+3)=-(35x^2-9)\)
- \(-4(-10x^2-7)=-(-38x^2+364)\)
- \(2(-6x^2-5)=-(4x^2+10)\)
- \(-2(-9x^2+10)=-(-13x^2+0)\)
- \(8x^2-128=0\)
- \(-5x^2+1125=0\)
- \(8x^2-8=0\)
Los de vierkantsvergelijking op zonder de discriminant te gebruiken
Verbetersleutel
- \(4x^2+0=0 \\
\Leftrightarrow 4x^2 = 0 \\
\Leftrightarrow x^2 = \frac{0}{4}\\
\Leftrightarrow x = 0 \\
V = \Big\{ 0 \Big\} \\ -----------------\)
- \(3x^2-7=8x^2-7 \\ \Leftrightarrow 3x^2-8x^2=-7+7 \\
\Leftrightarrow -5x^2 = 0 \\
\Leftrightarrow x^2 = \frac{0}{-5}\\
\Leftrightarrow x = 0 \\
V = \Big\{ 0 \Big\} \\ -----------------\)
- \(6x^2+864=0 \\
\Leftrightarrow 6x^2 = -864 \\
\Leftrightarrow x^2 = \frac{-864}{6} < 0 \\
V = \varnothing \\ -----------------\)
- \(-2(-4x^2-5)=-(-11x^2-310) \\ \Leftrightarrow 8x^2+10=11x^2+310 \\
\Leftrightarrow 8x^2-11x^2=310-10 \\
\Leftrightarrow -3x^2 = 300 \\
\Leftrightarrow x^2 = \frac{300}{-3} < 0 \\
V = \varnothing \\ -----------------\)
- \(-x^2-399=4x^2+6 \\ \Leftrightarrow -x^2-4x^2=6+399 \\
\Leftrightarrow -5x^2 = 405 \\
\Leftrightarrow x^2 = \frac{405}{-5} < 0 \\
V = \varnothing \\ -----------------\)
- \(3(-9x^2+3)=-(35x^2-9) \\ \Leftrightarrow -27x^2+9=-35x^2+9 \\
\Leftrightarrow -27x^2+35x^2=9-9 \\
\Leftrightarrow 8x^2 = 0 \\
\Leftrightarrow x^2 = \frac{0}{8}\\
\Leftrightarrow x = 0 \\
V = \Big\{ 0 \Big\} \\ -----------------\)
- \(-4(-10x^2-7)=-(-38x^2+364) \\ \Leftrightarrow 40x^2+28=38x^2-364 \\
\Leftrightarrow 40x^2-38x^2=-364-28 \\
\Leftrightarrow 2x^2 = -392 \\
\Leftrightarrow x^2 = \frac{-392}{2} < 0 \\
V = \varnothing \\ -----------------\)
- \(2(-6x^2-5)=-(4x^2+10) \\ \Leftrightarrow -12x^2-10=-4x^2-10 \\
\Leftrightarrow -12x^2+4x^2=-10+10 \\
\Leftrightarrow -8x^2 = 0 \\
\Leftrightarrow x^2 = \frac{0}{-8}\\
\Leftrightarrow x = 0 \\
V = \Big\{ 0 \Big\} \\ -----------------\)
- \(-2(-9x^2+10)=-(-13x^2+0) \\ \Leftrightarrow 18x^2-20=13x^2+0 \\
\Leftrightarrow 18x^2-13x^2=0+20 \\
\Leftrightarrow 5x^2 = 20 \\
\Leftrightarrow x^2 = \frac{20}{5}=4 \\
\Leftrightarrow x = 2 \vee x = -2 \\
V = \Big\{-2, 2 \Big\} \\ -----------------\)
- \(8x^2-128=0 \\
\Leftrightarrow 8x^2 = 128 \\
\Leftrightarrow x^2 = \frac{128}{8}=16 \\
\Leftrightarrow x = 4 \vee x = -4 \\
V = \Big\{-4, 4 \Big\} \\ -----------------\)
- \(-5x^2+1125=0 \\
\Leftrightarrow -5x^2 = -1125 \\
\Leftrightarrow x^2 = \frac{-1125}{-5}=225 \\
\Leftrightarrow x = 15 \vee x = -15 \\
V = \Big\{-15, 15 \Big\} \\ -----------------\)
- \(8x^2-8=0 \\
\Leftrightarrow 8x^2 = 8 \\
\Leftrightarrow x^2 = \frac{8}{8}=1 \\
\Leftrightarrow x = 1 \vee x = -1 \\
V = \Big\{-1, 1 \Big\} \\ -----------------\)