Los de vierkantsvergelijking op zonder de discriminant te gebruiken
- \(4(10x^2-5)=-(-35x^2+20)\)
- \(5(9x^2-7)=-(-40x^2-145)\)
- \(-4(-6x^2-5)=-(-26x^2-22)\)
- \(x^2+64=0\)
- \(-x^2+196=0\)
- \(14x^2+9=10x^2+9\)
- \(-5x^2-330=-3x^2+8\)
- \(-3(7x^2+6)=-(24x^2-90)\)
- \(x^2+209=3x^2+9\)
- \(-2(-3x^2+5)=-(0x^2-1340)\)
- \(-4x^2+144=0\)
- \(5x^2-20=0\)
Los de vierkantsvergelijking op zonder de discriminant te gebruiken
Verbetersleutel
- \(4(10x^2-5)=-(-35x^2+20) \\ \Leftrightarrow 40x^2-20=35x^2-20 \\
\Leftrightarrow 40x^2-35x^2=-20+20 \\
\Leftrightarrow 5x^2 = 0 \\
\Leftrightarrow x^2 = \frac{0}{5}\\
\Leftrightarrow x = 0 \\
V = \Big\{ 0 \Big\} \\ -----------------\)
- \(5(9x^2-7)=-(-40x^2-145) \\ \Leftrightarrow 45x^2-35=40x^2+145 \\
\Leftrightarrow 45x^2-40x^2=145+35 \\
\Leftrightarrow 5x^2 = 180 \\
\Leftrightarrow x^2 = \frac{180}{5}=36 \\
\Leftrightarrow x = 6 \vee x = -6 \\
V = \Big\{-6, 6 \Big\} \\ -----------------\)
- \(-4(-6x^2-5)=-(-26x^2-22) \\ \Leftrightarrow 24x^2+20=26x^2+22 \\
\Leftrightarrow 24x^2-26x^2=22-20 \\
\Leftrightarrow -2x^2 = 2 \\
\Leftrightarrow x^2 = \frac{2}{-2} < 0 \\
V = \varnothing \\ -----------------\)
- \(x^2+64=0 \\
\Leftrightarrow x^2 = -64 \\
\Leftrightarrow x^2 = \frac{-64}{1} < 0 \\
V = \varnothing \\ -----------------\)
- \(-x^2+196=0 \\
\Leftrightarrow -x^2 = -196 \\
\Leftrightarrow x^2 = \frac{-196}{-1}=196 \\
\Leftrightarrow x = 14 \vee x = -14 \\
V = \Big\{-14, 14 \Big\} \\ -----------------\)
- \(14x^2+9=10x^2+9 \\ \Leftrightarrow 14x^2-10x^2=9-9 \\
\Leftrightarrow 4x^2 = 0 \\
\Leftrightarrow x^2 = \frac{0}{4}\\
\Leftrightarrow x = 0 \\
V = \Big\{ 0 \Big\} \\ -----------------\)
- \(-5x^2-330=-3x^2+8 \\ \Leftrightarrow -5x^2+3x^2=8+330 \\
\Leftrightarrow -2x^2 = 338 \\
\Leftrightarrow x^2 = \frac{338}{-2} < 0 \\
V = \varnothing \\ -----------------\)
- \(-3(7x^2+6)=-(24x^2-90) \\ \Leftrightarrow -21x^2-18=-24x^2+90 \\
\Leftrightarrow -21x^2+24x^2=90+18 \\
\Leftrightarrow 3x^2 = 108 \\
\Leftrightarrow x^2 = \frac{108}{3}=36 \\
\Leftrightarrow x = 6 \vee x = -6 \\
V = \Big\{-6, 6 \Big\} \\ -----------------\)
- \(x^2+209=3x^2+9 \\ \Leftrightarrow x^2-3x^2=9-209 \\
\Leftrightarrow -2x^2 = -200 \\
\Leftrightarrow x^2 = \frac{-200}{-2}=100 \\
\Leftrightarrow x = 10 \vee x = -10 \\
V = \Big\{-10, 10 \Big\} \\ -----------------\)
- \(-2(-3x^2+5)=-(0x^2-1340) \\ \Leftrightarrow 6x^2-10=0x^2+1340 \\
\Leftrightarrow 6x^2+0x^2=1340+10 \\
\Leftrightarrow 6x^2 = 1350 \\
\Leftrightarrow x^2 = \frac{1350}{6}=225 \\
\Leftrightarrow x = 15 \vee x = -15 \\
V = \Big\{-15, 15 \Big\} \\ -----------------\)
- \(-4x^2+144=0 \\
\Leftrightarrow -4x^2 = -144 \\
\Leftrightarrow x^2 = \frac{-144}{-4}=36 \\
\Leftrightarrow x = 6 \vee x = -6 \\
V = \Big\{-6, 6 \Big\} \\ -----------------\)
- \(5x^2-20=0 \\
\Leftrightarrow 5x^2 = 20 \\
\Leftrightarrow x^2 = \frac{20}{5}=4 \\
\Leftrightarrow x = 2 \vee x = -2 \\
V = \Big\{-2, 2 \Big\} \\ -----------------\)