Los de vierkantsvergelijking op zonder de discriminant te gebruiken
- \(-4x^2+64=0\)
- \(-4(2x^2+4)=-(2x^2+22)\)
- \(4x^2-576=0\)
- \(-5x^2-320=0\)
- \(-5x^2-245=0\)
- \(x^2-515=-2x^2-8\)
- \(4(-9x^2-4)=-(43x^2-236)\)
- \(-5x^2+5=0\)
- \(11x^2+1=10x^2-8\)
- \(8x^2+1352=0\)
- \(-5x^2+20=0\)
- \(x^2+679=5x^2+3\)
Los de vierkantsvergelijking op zonder de discriminant te gebruiken
Verbetersleutel
- \(-4x^2+64=0 \\
\Leftrightarrow -4x^2 = -64 \\
\Leftrightarrow x^2 = \frac{-64}{-4}=16 \\
\Leftrightarrow x = 4 \vee x = -4 \\
V = \Big\{-4, 4 \Big\} \\ -----------------\)
- \(-4(2x^2+4)=-(2x^2+22) \\ \Leftrightarrow -8x^2-16=-2x^2-22 \\
\Leftrightarrow -8x^2+2x^2=-22+16 \\
\Leftrightarrow -6x^2 = -6 \\
\Leftrightarrow x^2 = \frac{-6}{-6}=1 \\
\Leftrightarrow x = 1 \vee x = -1 \\
V = \Big\{-1, 1 \Big\} \\ -----------------\)
- \(4x^2-576=0 \\
\Leftrightarrow 4x^2 = 576 \\
\Leftrightarrow x^2 = \frac{576}{4}=144 \\
\Leftrightarrow x = 12 \vee x = -12 \\
V = \Big\{-12, 12 \Big\} \\ -----------------\)
- \(-5x^2-320=0 \\
\Leftrightarrow -5x^2 = 320 \\
\Leftrightarrow x^2 = \frac{320}{-5} < 0 \\
V = \varnothing \\ -----------------\)
- \(-5x^2-245=0 \\
\Leftrightarrow -5x^2 = 245 \\
\Leftrightarrow x^2 = \frac{245}{-5} < 0 \\
V = \varnothing \\ -----------------\)
- \(x^2-515=-2x^2-8 \\ \Leftrightarrow x^2+2x^2=-8+515 \\
\Leftrightarrow 3x^2 = 507 \\
\Leftrightarrow x^2 = \frac{507}{3}=169 \\
\Leftrightarrow x = 13 \vee x = -13 \\
V = \Big\{-13, 13 \Big\} \\ -----------------\)
- \(4(-9x^2-4)=-(43x^2-236) \\ \Leftrightarrow -36x^2-16=-43x^2+236 \\
\Leftrightarrow -36x^2+43x^2=236+16 \\
\Leftrightarrow 7x^2 = 252 \\
\Leftrightarrow x^2 = \frac{252}{7}=36 \\
\Leftrightarrow x = 6 \vee x = -6 \\
V = \Big\{-6, 6 \Big\} \\ -----------------\)
- \(-5x^2+5=0 \\
\Leftrightarrow -5x^2 = -5 \\
\Leftrightarrow x^2 = \frac{-5}{-5}=1 \\
\Leftrightarrow x = 1 \vee x = -1 \\
V = \Big\{-1, 1 \Big\} \\ -----------------\)
- \(11x^2+1=10x^2-8 \\ \Leftrightarrow 11x^2-10x^2=-8-1 \\
\Leftrightarrow x^2 = -9 \\
\Leftrightarrow x^2 = \frac{-9}{1} < 0 \\
V = \varnothing \\ -----------------\)
- \(8x^2+1352=0 \\
\Leftrightarrow 8x^2 = -1352 \\
\Leftrightarrow x^2 = \frac{-1352}{8} < 0 \\
V = \varnothing \\ -----------------\)
- \(-5x^2+20=0 \\
\Leftrightarrow -5x^2 = -20 \\
\Leftrightarrow x^2 = \frac{-20}{-5}=4 \\
\Leftrightarrow x = 2 \vee x = -2 \\
V = \Big\{-2, 2 \Big\} \\ -----------------\)
- \(x^2+679=5x^2+3 \\ \Leftrightarrow x^2-5x^2=3-679 \\
\Leftrightarrow -4x^2 = -676 \\
\Leftrightarrow x^2 = \frac{-676}{-4}=169 \\
\Leftrightarrow x = 13 \vee x = -13 \\
V = \Big\{-13, 13 \Big\} \\ -----------------\)