Los de vierkantsvergelijking op zonder de discriminant te gebruiken
- \(-4x^2+784=0\)
- \(2(3x^2-2)=-(-4x^2-446)\)
- \(-4(-3x^2+6)=-(-20x^2+312)\)
- \(3x^2+6=2x^2+5\)
- \(-4(7x^2+8)=-(22x^2-694)\)
- \(-2(10x^2+6)=-(24x^2+268)\)
- \(-8x^2+1568=0\)
- \(-2x^2+68=6x^2-4\)
- \(-9x^2-593=-6x^2-5\)
- \(5x^2-1125=0\)
- \(-x^2-25=0\)
- \(-5x^2+53=-10x^2+8\)
Los de vierkantsvergelijking op zonder de discriminant te gebruiken
Verbetersleutel
- \(-4x^2+784=0 \\
\Leftrightarrow -4x^2 = -784 \\
\Leftrightarrow x^2 = \frac{-784}{-4}=196 \\
\Leftrightarrow x = 14 \vee x = -14 \\
V = \Big\{-14, 14 \Big\} \\ -----------------\)
- \(2(3x^2-2)=-(-4x^2-446) \\ \Leftrightarrow 6x^2-4=4x^2+446 \\
\Leftrightarrow 6x^2-4x^2=446+4 \\
\Leftrightarrow 2x^2 = 450 \\
\Leftrightarrow x^2 = \frac{450}{2}=225 \\
\Leftrightarrow x = 15 \vee x = -15 \\
V = \Big\{-15, 15 \Big\} \\ -----------------\)
- \(-4(-3x^2+6)=-(-20x^2+312) \\ \Leftrightarrow 12x^2-24=20x^2-312 \\
\Leftrightarrow 12x^2-20x^2=-312+24 \\
\Leftrightarrow -8x^2 = -288 \\
\Leftrightarrow x^2 = \frac{-288}{-8}=36 \\
\Leftrightarrow x = 6 \vee x = -6 \\
V = \Big\{-6, 6 \Big\} \\ -----------------\)
- \(3x^2+6=2x^2+5 \\ \Leftrightarrow 3x^2-2x^2=5-6 \\
\Leftrightarrow x^2 = -1 \\
\Leftrightarrow x^2 = \frac{-1}{1} < 0 \\
V = \varnothing \\ -----------------\)
- \(-4(7x^2+8)=-(22x^2-694) \\ \Leftrightarrow -28x^2-32=-22x^2+694 \\
\Leftrightarrow -28x^2+22x^2=694+32 \\
\Leftrightarrow -6x^2 = 726 \\
\Leftrightarrow x^2 = \frac{726}{-6} < 0 \\
V = \varnothing \\ -----------------\)
- \(-2(10x^2+6)=-(24x^2+268) \\ \Leftrightarrow -20x^2-12=-24x^2-268 \\
\Leftrightarrow -20x^2+24x^2=-268+12 \\
\Leftrightarrow 4x^2 = -256 \\
\Leftrightarrow x^2 = \frac{-256}{4} < 0 \\
V = \varnothing \\ -----------------\)
- \(-8x^2+1568=0 \\
\Leftrightarrow -8x^2 = -1568 \\
\Leftrightarrow x^2 = \frac{-1568}{-8}=196 \\
\Leftrightarrow x = 14 \vee x = -14 \\
V = \Big\{-14, 14 \Big\} \\ -----------------\)
- \(-2x^2+68=6x^2-4 \\ \Leftrightarrow -2x^2-6x^2=-4-68 \\
\Leftrightarrow -8x^2 = -72 \\
\Leftrightarrow x^2 = \frac{-72}{-8}=9 \\
\Leftrightarrow x = 3 \vee x = -3 \\
V = \Big\{-3, 3 \Big\} \\ -----------------\)
- \(-9x^2-593=-6x^2-5 \\ \Leftrightarrow -9x^2+6x^2=-5+593 \\
\Leftrightarrow -3x^2 = 588 \\
\Leftrightarrow x^2 = \frac{588}{-3} < 0 \\
V = \varnothing \\ -----------------\)
- \(5x^2-1125=0 \\
\Leftrightarrow 5x^2 = 1125 \\
\Leftrightarrow x^2 = \frac{1125}{5}=225 \\
\Leftrightarrow x = 15 \vee x = -15 \\
V = \Big\{-15, 15 \Big\} \\ -----------------\)
- \(-x^2-25=0 \\
\Leftrightarrow -x^2 = 25 \\
\Leftrightarrow x^2 = \frac{25}{-1} < 0 \\
V = \varnothing \\ -----------------\)
- \(-5x^2+53=-10x^2+8 \\ \Leftrightarrow -5x^2+10x^2=8-53 \\
\Leftrightarrow 5x^2 = -45 \\
\Leftrightarrow x^2 = \frac{-45}{5} < 0 \\
V = \varnothing \\ -----------------\)