Los de vierkantsvergelijking op zonder de discriminant te gebruiken
- \(-5(-7x^2+7)=-(-38x^2+62)\)
- \(14x^2-787=10x^2-3\)
- \(-8x^2-8=-3x^2-8\)
- \(-x^2+196=0\)
- \(7x^2+28=0\)
- \(-5(-6x^2+4)=-(-22x^2+20)\)
- \(-14x^2+153=-8x^2+3\)
- \(-8x^2-288=0\)
- \(2x^2-98=0\)
- \(6x^2-54=0\)
- \(6x^2-294=0\)
- \(-3x^2-48=0\)
Los de vierkantsvergelijking op zonder de discriminant te gebruiken
Verbetersleutel
- \(-5(-7x^2+7)=-(-38x^2+62) \\ \Leftrightarrow 35x^2-35=38x^2-62 \\
\Leftrightarrow 35x^2-38x^2=-62+35 \\
\Leftrightarrow -3x^2 = -27 \\
\Leftrightarrow x^2 = \frac{-27}{-3}=9 \\
\Leftrightarrow x = 3 \vee x = -3 \\
V = \Big\{-3, 3 \Big\} \\ -----------------\)
- \(14x^2-787=10x^2-3 \\ \Leftrightarrow 14x^2-10x^2=-3+787 \\
\Leftrightarrow 4x^2 = 784 \\
\Leftrightarrow x^2 = \frac{784}{4}=196 \\
\Leftrightarrow x = 14 \vee x = -14 \\
V = \Big\{-14, 14 \Big\} \\ -----------------\)
- \(-8x^2-8=-3x^2-8 \\ \Leftrightarrow -8x^2+3x^2=-8+8 \\
\Leftrightarrow -5x^2 = 0 \\
\Leftrightarrow x^2 = \frac{0}{-5}\\
\Leftrightarrow x = 0 \\
V = \Big\{ 0 \Big\} \\ -----------------\)
- \(-x^2+196=0 \\
\Leftrightarrow -x^2 = -196 \\
\Leftrightarrow x^2 = \frac{-196}{-1}=196 \\
\Leftrightarrow x = 14 \vee x = -14 \\
V = \Big\{-14, 14 \Big\} \\ -----------------\)
- \(7x^2+28=0 \\
\Leftrightarrow 7x^2 = -28 \\
\Leftrightarrow x^2 = \frac{-28}{7} < 0 \\
V = \varnothing \\ -----------------\)
- \(-5(-6x^2+4)=-(-22x^2+20) \\ \Leftrightarrow 30x^2-20=22x^2-20 \\
\Leftrightarrow 30x^2-22x^2=-20+20 \\
\Leftrightarrow 8x^2 = 0 \\
\Leftrightarrow x^2 = \frac{0}{8}\\
\Leftrightarrow x = 0 \\
V = \Big\{ 0 \Big\} \\ -----------------\)
- \(-14x^2+153=-8x^2+3 \\ \Leftrightarrow -14x^2+8x^2=3-153 \\
\Leftrightarrow -6x^2 = -150 \\
\Leftrightarrow x^2 = \frac{-150}{-6}=25 \\
\Leftrightarrow x = 5 \vee x = -5 \\
V = \Big\{-5, 5 \Big\} \\ -----------------\)
- \(-8x^2-288=0 \\
\Leftrightarrow -8x^2 = 288 \\
\Leftrightarrow x^2 = \frac{288}{-8} < 0 \\
V = \varnothing \\ -----------------\)
- \(2x^2-98=0 \\
\Leftrightarrow 2x^2 = 98 \\
\Leftrightarrow x^2 = \frac{98}{2}=49 \\
\Leftrightarrow x = 7 \vee x = -7 \\
V = \Big\{-7, 7 \Big\} \\ -----------------\)
- \(6x^2-54=0 \\
\Leftrightarrow 6x^2 = 54 \\
\Leftrightarrow x^2 = \frac{54}{6}=9 \\
\Leftrightarrow x = 3 \vee x = -3 \\
V = \Big\{-3, 3 \Big\} \\ -----------------\)
- \(6x^2-294=0 \\
\Leftrightarrow 6x^2 = 294 \\
\Leftrightarrow x^2 = \frac{294}{6}=49 \\
\Leftrightarrow x = 7 \vee x = -7 \\
V = \Big\{-7, 7 \Big\} \\ -----------------\)
- \(-3x^2-48=0 \\
\Leftrightarrow -3x^2 = 48 \\
\Leftrightarrow x^2 = \frac{48}{-3} < 0 \\
V = \varnothing \\ -----------------\)