Los de vierkantsvergelijking op zonder de discriminant te gebruiken
- \(-5x^2-845=0\)
- \(2x^2-162=0\)
- \(12x^2-579=9x^2+9\)
- \(-2(-7x^2-10)=-(-18x^2+380)\)
- \(-14x^2-390=-6x^2+2\)
- \(-5(8x^2-2)=-(41x^2-14)\)
- \(4(-2x^2+10)=-(15x^2-152)\)
- \(-5(4x^2+6)=-(18x^2+32)\)
- \(-3x^2-156=-9x^2-6\)
- \(-6x^2+0=0\)
- \(-5x^2+605=0\)
- \(-5(-9x^2+6)=-(-38x^2-313)\)
Los de vierkantsvergelijking op zonder de discriminant te gebruiken
Verbetersleutel
- \(-5x^2-845=0 \\
\Leftrightarrow -5x^2 = 845 \\
\Leftrightarrow x^2 = \frac{845}{-5} < 0 \\
V = \varnothing \\ -----------------\)
- \(2x^2-162=0 \\
\Leftrightarrow 2x^2 = 162 \\
\Leftrightarrow x^2 = \frac{162}{2}=81 \\
\Leftrightarrow x = 9 \vee x = -9 \\
V = \Big\{-9, 9 \Big\} \\ -----------------\)
- \(12x^2-579=9x^2+9 \\ \Leftrightarrow 12x^2-9x^2=9+579 \\
\Leftrightarrow 3x^2 = 588 \\
\Leftrightarrow x^2 = \frac{588}{3}=196 \\
\Leftrightarrow x = 14 \vee x = -14 \\
V = \Big\{-14, 14 \Big\} \\ -----------------\)
- \(-2(-7x^2-10)=-(-18x^2+380) \\ \Leftrightarrow 14x^2+20=18x^2-380 \\
\Leftrightarrow 14x^2-18x^2=-380-20 \\
\Leftrightarrow -4x^2 = -400 \\
\Leftrightarrow x^2 = \frac{-400}{-4}=100 \\
\Leftrightarrow x = 10 \vee x = -10 \\
V = \Big\{-10, 10 \Big\} \\ -----------------\)
- \(-14x^2-390=-6x^2+2 \\ \Leftrightarrow -14x^2+6x^2=2+390 \\
\Leftrightarrow -8x^2 = 392 \\
\Leftrightarrow x^2 = \frac{392}{-8} < 0 \\
V = \varnothing \\ -----------------\)
- \(-5(8x^2-2)=-(41x^2-14) \\ \Leftrightarrow -40x^2+10=-41x^2+14 \\
\Leftrightarrow -40x^2+41x^2=14-10 \\
\Leftrightarrow x^2 = 4 \\
\Leftrightarrow x^2 = \frac{4}{1}=4 \\
\Leftrightarrow x = 2 \vee x = -2 \\
V = \Big\{-2, 2 \Big\} \\ -----------------\)
- \(4(-2x^2+10)=-(15x^2-152) \\ \Leftrightarrow -8x^2+40=-15x^2+152 \\
\Leftrightarrow -8x^2+15x^2=152-40 \\
\Leftrightarrow 7x^2 = 112 \\
\Leftrightarrow x^2 = \frac{112}{7}=16 \\
\Leftrightarrow x = 4 \vee x = -4 \\
V = \Big\{-4, 4 \Big\} \\ -----------------\)
- \(-5(4x^2+6)=-(18x^2+32) \\ \Leftrightarrow -20x^2-30=-18x^2-32 \\
\Leftrightarrow -20x^2+18x^2=-32+30 \\
\Leftrightarrow -2x^2 = -2 \\
\Leftrightarrow x^2 = \frac{-2}{-2}=1 \\
\Leftrightarrow x = 1 \vee x = -1 \\
V = \Big\{-1, 1 \Big\} \\ -----------------\)
- \(-3x^2-156=-9x^2-6 \\ \Leftrightarrow -3x^2+9x^2=-6+156 \\
\Leftrightarrow 6x^2 = 150 \\
\Leftrightarrow x^2 = \frac{150}{6}=25 \\
\Leftrightarrow x = 5 \vee x = -5 \\
V = \Big\{-5, 5 \Big\} \\ -----------------\)
- \(-6x^2+0=0 \\
\Leftrightarrow -6x^2 = 0 \\
\Leftrightarrow x^2 = \frac{0}{-6}\\
\Leftrightarrow x = 0 \\
V = \Big\{ 0 \Big\} \\ -----------------\)
- \(-5x^2+605=0 \\
\Leftrightarrow -5x^2 = -605 \\
\Leftrightarrow x^2 = \frac{-605}{-5}=121 \\
\Leftrightarrow x = 11 \vee x = -11 \\
V = \Big\{-11, 11 \Big\} \\ -----------------\)
- \(-5(-9x^2+6)=-(-38x^2-313) \\ \Leftrightarrow 45x^2-30=38x^2+313 \\
\Leftrightarrow 45x^2-38x^2=313+30 \\
\Leftrightarrow 7x^2 = 343 \\
\Leftrightarrow x^2 = \frac{343}{7}=49 \\
\Leftrightarrow x = 7 \vee x = -7 \\
V = \Big\{-7, 7 \Big\} \\ -----------------\)