Los de vierkantsvergelijking op zonder de discriminant te gebruiken
- \(-8x^2-159=-10x^2+3\)
- \(-2(-7x^2+8)=-(-20x^2-80)\)
- \(2x^2+24=10x^2-8\)
- \(5(2x^2+10)=-(-2x^2-42)\)
- \(2x^2-50=0\)
- \(7x^2-112=0\)
- \(-12x^2-293=-4x^2-5\)
- \(5(9x^2-3)=-(-52x^2+862)\)
- \(3(9x^2-9)=-(-29x^2+27)\)
- \(12x^2+1178=5x^2-5\)
- \(-2x^2-18=0\)
- \(-4(2x^2+6)=-(15x^2-39)\)
Los de vierkantsvergelijking op zonder de discriminant te gebruiken
Verbetersleutel
- \(-8x^2-159=-10x^2+3 \\ \Leftrightarrow -8x^2+10x^2=3+159 \\
\Leftrightarrow 2x^2 = 162 \\
\Leftrightarrow x^2 = \frac{162}{2}=81 \\
\Leftrightarrow x = 9 \vee x = -9 \\
V = \Big\{-9, 9 \Big\} \\ -----------------\)
- \(-2(-7x^2+8)=-(-20x^2-80) \\ \Leftrightarrow 14x^2-16=20x^2+80 \\
\Leftrightarrow 14x^2-20x^2=80+16 \\
\Leftrightarrow -6x^2 = 96 \\
\Leftrightarrow x^2 = \frac{96}{-6} < 0 \\
V = \varnothing \\ -----------------\)
- \(2x^2+24=10x^2-8 \\ \Leftrightarrow 2x^2-10x^2=-8-24 \\
\Leftrightarrow -8x^2 = -32 \\
\Leftrightarrow x^2 = \frac{-32}{-8}=4 \\
\Leftrightarrow x = 2 \vee x = -2 \\
V = \Big\{-2, 2 \Big\} \\ -----------------\)
- \(5(2x^2+10)=-(-2x^2-42) \\ \Leftrightarrow 10x^2+50=2x^2+42 \\
\Leftrightarrow 10x^2-2x^2=42-50 \\
\Leftrightarrow 8x^2 = -8 \\
\Leftrightarrow x^2 = \frac{-8}{8} < 0 \\
V = \varnothing \\ -----------------\)
- \(2x^2-50=0 \\
\Leftrightarrow 2x^2 = 50 \\
\Leftrightarrow x^2 = \frac{50}{2}=25 \\
\Leftrightarrow x = 5 \vee x = -5 \\
V = \Big\{-5, 5 \Big\} \\ -----------------\)
- \(7x^2-112=0 \\
\Leftrightarrow 7x^2 = 112 \\
\Leftrightarrow x^2 = \frac{112}{7}=16 \\
\Leftrightarrow x = 4 \vee x = -4 \\
V = \Big\{-4, 4 \Big\} \\ -----------------\)
- \(-12x^2-293=-4x^2-5 \\ \Leftrightarrow -12x^2+4x^2=-5+293 \\
\Leftrightarrow -8x^2 = 288 \\
\Leftrightarrow x^2 = \frac{288}{-8} < 0 \\
V = \varnothing \\ -----------------\)
- \(5(9x^2-3)=-(-52x^2+862) \\ \Leftrightarrow 45x^2-15=52x^2-862 \\
\Leftrightarrow 45x^2-52x^2=-862+15 \\
\Leftrightarrow -7x^2 = -847 \\
\Leftrightarrow x^2 = \frac{-847}{-7}=121 \\
\Leftrightarrow x = 11 \vee x = -11 \\
V = \Big\{-11, 11 \Big\} \\ -----------------\)
- \(3(9x^2-9)=-(-29x^2+27) \\ \Leftrightarrow 27x^2-27=29x^2-27 \\
\Leftrightarrow 27x^2-29x^2=-27+27 \\
\Leftrightarrow -2x^2 = 0 \\
\Leftrightarrow x^2 = \frac{0}{-2}\\
\Leftrightarrow x = 0 \\
V = \Big\{ 0 \Big\} \\ -----------------\)
- \(12x^2+1178=5x^2-5 \\ \Leftrightarrow 12x^2-5x^2=-5-1178 \\
\Leftrightarrow 7x^2 = -1183 \\
\Leftrightarrow x^2 = \frac{-1183}{7} < 0 \\
V = \varnothing \\ -----------------\)
- \(-2x^2-18=0 \\
\Leftrightarrow -2x^2 = 18 \\
\Leftrightarrow x^2 = \frac{18}{-2} < 0 \\
V = \varnothing \\ -----------------\)
- \(-4(2x^2+6)=-(15x^2-39) \\ \Leftrightarrow -8x^2-24=-15x^2+39 \\
\Leftrightarrow -8x^2+15x^2=39+24 \\
\Leftrightarrow 7x^2 = 63 \\
\Leftrightarrow x^2 = \frac{63}{7}=9 \\
\Leftrightarrow x = 3 \vee x = -3 \\
V = \Big\{-3, 3 \Big\} \\ -----------------\)