Los de vierkantsvergelijking op zonder de discriminant te gebruiken
- \(x^2-17x=9x^2-9x\)
- \(5(-4x^2-8x)=-(17x^2+63x)\)
- \(4x^2+19x=0\)
- \(-6x^2-27x=-7x^2-4x\)
- \(5x^2+15x=3x^2-5x\)
- \(-8x^2+20x=0\)
- \(4(4x^2-6x)=-(-11x^2+26x)\)
- \(2x^2+1x=0\)
- \(3(-2x^2-5x)=-(13x^2+17x)\)
- \(8x^2-11x=0\)
- \(-5x^2+15x=0\)
- \(-2(5x^2-5x)=-(17x^2-x)\)
Los de vierkantsvergelijking op zonder de discriminant te gebruiken
Verbetersleutel
- \(x^2-17x=9x^2-9x \\ \Leftrightarrow -8x^2-8x=0 \\
\Leftrightarrow x(-8x-8) = 0 \\
\Leftrightarrow x = 0 \vee -8x-8=0 \\
\Leftrightarrow x = 0 \vee x = \frac{8}{-8} = -1 \\ V = \Big\{ 0 ; -1 \Big\} \\ -----------------\)
- \(5(-4x^2-8x)=-(17x^2+63x) \\ \Leftrightarrow -20x^2-40x=-17x^2-63x \\
\Leftrightarrow -20x^2-40x+17x^2+63x= 0 \\
\Leftrightarrow -3x^2-23x=0 \\
\Leftrightarrow x(-3x-23) = 0 \\
\Leftrightarrow x = 0 \vee -3x-23=0 \\
\Leftrightarrow x = 0 \vee x = \frac{23}{-3} = \frac{-23}{3} \\ V = \Big\{ 0 ; \frac{-23}{3} \Big\} \\ -----------------\)
- \(4x^2+19x=0 \\
\Leftrightarrow x(4x+19) = 0 \\
\Leftrightarrow x = 0 \vee 4x+19=0 \\
\Leftrightarrow x = 0 \vee x = \frac{-19}{4} \\ V = \Big\{ 0 ; \frac{-19}{4} \Big\} \\ -----------------\)
- \(-6x^2-27x=-7x^2-4x \\ \Leftrightarrow x^2-23x=0 \\
\Leftrightarrow x(x-23) = 0 \\
\Leftrightarrow x = 0 \vee x-23=0 \\
\Leftrightarrow x = 0 \vee x = \frac{23}{1} = 23 \\ V = \Big\{ 23; 0 \Big\} \\ -----------------\)
- \(5x^2+15x=3x^2-5x \\ \Leftrightarrow 2x^2+20x=0 \\
\Leftrightarrow x(2x+20) = 0 \\
\Leftrightarrow x = 0 \vee 2x+20=0 \\
\Leftrightarrow x = 0 \vee x = \frac{-20}{2} = -10 \\ V = \Big\{ 0 ; -10 \Big\} \\ -----------------\)
- \(-8x^2+20x=0 \\
\Leftrightarrow x(-8x+20) = 0 \\
\Leftrightarrow x = 0 \vee -8x+20=0 \\
\Leftrightarrow x = 0 \vee x = \frac{-20}{-8} = \frac{5}{2} \\ V = \Big\{ \frac{5}{2}; 0 \Big\} \\ -----------------\)
- \(4(4x^2-6x)=-(-11x^2+26x) \\ \Leftrightarrow 16x^2-24x=11x^2-26x \\
\Leftrightarrow 16x^2-24x-11x^2+26x= 0 \\
\Leftrightarrow 5x^2-2x=0 \\
\Leftrightarrow x(5x-2) = 0 \\
\Leftrightarrow x = 0 \vee 5x-2=0 \\
\Leftrightarrow x = 0 \vee x = \frac{2}{5} \\ V = \Big\{ \frac{2}{5}; 0 \Big\} \\ -----------------\)
- \(2x^2+1x=0 \\
\Leftrightarrow x(2x+1) = 0 \\
\Leftrightarrow x = 0 \vee 2x+1=0 \\
\Leftrightarrow x = 0 \vee x = \frac{-1}{2} \\ V = \Big\{ 0 ; \frac{-1}{2} \Big\} \\ -----------------\)
- \(3(-2x^2-5x)=-(13x^2+17x) \\ \Leftrightarrow -6x^2-15x=-13x^2-17x \\
\Leftrightarrow -6x^2-15x+13x^2+17x= 0 \\
\Leftrightarrow 7x^2-2x=0 \\
\Leftrightarrow x(7x-2) = 0 \\
\Leftrightarrow x = 0 \vee 7x-2=0 \\
\Leftrightarrow x = 0 \vee x = \frac{2}{7} \\ V = \Big\{ \frac{2}{7}; 0 \Big\} \\ -----------------\)
- \(8x^2-11x=0 \\
\Leftrightarrow x(8x-11) = 0 \\
\Leftrightarrow x = 0 \vee 8x-11=0 \\
\Leftrightarrow x = 0 \vee x = \frac{11}{8} \\ V = \Big\{ \frac{11}{8}; 0 \Big\} \\ -----------------\)
- \(-5x^2+15x=0 \\
\Leftrightarrow x(-5x+15) = 0 \\
\Leftrightarrow x = 0 \vee -5x+15=0 \\
\Leftrightarrow x = 0 \vee x = \frac{-15}{-5} = 3 \\ V = \Big\{ 3; 0 \Big\} \\ -----------------\)
- \(-2(5x^2-5x)=-(17x^2-x) \\ \Leftrightarrow -10x^2+10x=-17x^2+x \\
\Leftrightarrow -10x^2+10x+17x^2-x= 0 \\
\Leftrightarrow 7x^2-9x=0 \\
\Leftrightarrow x(7x-9) = 0 \\
\Leftrightarrow x = 0 \vee 7x-9=0 \\
\Leftrightarrow x = 0 \vee x = \frac{9}{7} \\ V = \Big\{ \frac{9}{7}; 0 \Big\} \\ -----------------\)