Los de vierkantsvergelijking op zonder de discriminant te gebruiken
- \(4x^2+138=7x^2-9\)
- \(-2(-8x^2+6)=-(-20x^2+12)\)
- \(-8x^2-968=0\)
- \(2x^2+32=0\)
- \(-4(6x^2-8)=-(32x^2+168)\)
- \(2(3x^2+6)=-(-5x^2-12)\)
- \(13x^2+181=6x^2+6\)
- \(6x^2-600=0\)
- \(-4(-5x^2-9)=-(-24x^2+64)\)
- \(8x^2-392=0\)
- \(4(4x^2+3)=-(-23x^2-187)\)
- \(5x^2-125=0\)
Los de vierkantsvergelijking op zonder de discriminant te gebruiken
Verbetersleutel
- \(4x^2+138=7x^2-9 \\ \Leftrightarrow 4x^2-7x^2=-9-138 \\
\Leftrightarrow -3x^2 = -147 \\
\Leftrightarrow x^2 = \frac{-147}{-3}=49 \\
\Leftrightarrow x = 7 \vee x = -7 \\
V = \Big\{-7, 7 \Big\} \\ -----------------\)
- \(-2(-8x^2+6)=-(-20x^2+12) \\ \Leftrightarrow 16x^2-12=20x^2-12 \\
\Leftrightarrow 16x^2-20x^2=-12+12 \\
\Leftrightarrow -4x^2 = 0 \\
\Leftrightarrow x^2 = \frac{0}{-4}\\
\Leftrightarrow x = 0 \\
V = \Big\{ 0 \Big\} \\ -----------------\)
- \(-8x^2-968=0 \\
\Leftrightarrow -8x^2 = 968 \\
\Leftrightarrow x^2 = \frac{968}{-8} < 0 \\
V = \varnothing \\ -----------------\)
- \(2x^2+32=0 \\
\Leftrightarrow 2x^2 = -32 \\
\Leftrightarrow x^2 = \frac{-32}{2} < 0 \\
V = \varnothing \\ -----------------\)
- \(-4(6x^2-8)=-(32x^2+168) \\ \Leftrightarrow -24x^2+32=-32x^2-168 \\
\Leftrightarrow -24x^2+32x^2=-168-32 \\
\Leftrightarrow 8x^2 = -200 \\
\Leftrightarrow x^2 = \frac{-200}{8} < 0 \\
V = \varnothing \\ -----------------\)
- \(2(3x^2+6)=-(-5x^2-12) \\ \Leftrightarrow 6x^2+12=5x^2+12 \\
\Leftrightarrow 6x^2-5x^2=12-12 \\
\Leftrightarrow x^2 = 0 \\
\Leftrightarrow x^2 = \frac{0}{1}\\
\Leftrightarrow x = 0 \\
V = \Big\{ 0 \Big\} \\ -----------------\)
- \(13x^2+181=6x^2+6 \\ \Leftrightarrow 13x^2-6x^2=6-181 \\
\Leftrightarrow 7x^2 = -175 \\
\Leftrightarrow x^2 = \frac{-175}{7} < 0 \\
V = \varnothing \\ -----------------\)
- \(6x^2-600=0 \\
\Leftrightarrow 6x^2 = 600 \\
\Leftrightarrow x^2 = \frac{600}{6}=100 \\
\Leftrightarrow x = 10 \vee x = -10 \\
V = \Big\{-10, 10 \Big\} \\ -----------------\)
- \(-4(-5x^2-9)=-(-24x^2+64) \\ \Leftrightarrow 20x^2+36=24x^2-64 \\
\Leftrightarrow 20x^2-24x^2=-64-36 \\
\Leftrightarrow -4x^2 = -100 \\
\Leftrightarrow x^2 = \frac{-100}{-4}=25 \\
\Leftrightarrow x = 5 \vee x = -5 \\
V = \Big\{-5, 5 \Big\} \\ -----------------\)
- \(8x^2-392=0 \\
\Leftrightarrow 8x^2 = 392 \\
\Leftrightarrow x^2 = \frac{392}{8}=49 \\
\Leftrightarrow x = 7 \vee x = -7 \\
V = \Big\{-7, 7 \Big\} \\ -----------------\)
- \(4(4x^2+3)=-(-23x^2-187) \\ \Leftrightarrow 16x^2+12=23x^2+187 \\
\Leftrightarrow 16x^2-23x^2=187-12 \\
\Leftrightarrow -7x^2 = 175 \\
\Leftrightarrow x^2 = \frac{175}{-7} < 0 \\
V = \varnothing \\ -----------------\)
- \(5x^2-125=0 \\
\Leftrightarrow 5x^2 = 125 \\
\Leftrightarrow x^2 = \frac{125}{5}=25 \\
\Leftrightarrow x = 5 \vee x = -5 \\
V = \Big\{-5, 5 \Big\} \\ -----------------\)