Los de vierkantsvergelijking op zonder de discriminant te gebruiken
- \(3x^2+1184=9x^2+8\)
- \(-3(-4x^2-7)=-(-11x^2+28)\)
- \(-3x^2+675=0\)
- \(-5(-9x^2+5)=-(-48x^2-650)\)
- \(-2x^2-668=-6x^2+8\)
- \(-5(4x^2-3)=-(13x^2+48)\)
- \(7x^2-343=0\)
- \(7x^2-1372=0\)
- \(5(-8x^2-5)=-(35x^2+430)\)
- \(-5(-5x^2-4)=-(-24x^2-141)\)
- \(-2x^2-855=-7x^2-10\)
- \(3(5x^2+8)=-(-23x^2-24)\)
Los de vierkantsvergelijking op zonder de discriminant te gebruiken
Verbetersleutel
- \(3x^2+1184=9x^2+8 \\ \Leftrightarrow 3x^2-9x^2=8-1184 \\
\Leftrightarrow -6x^2 = -1176 \\
\Leftrightarrow x^2 = \frac{-1176}{-6}=196 \\
\Leftrightarrow x = 14 \vee x = -14 \\
V = \Big\{-14, 14 \Big\} \\ -----------------\)
- \(-3(-4x^2-7)=-(-11x^2+28) \\ \Leftrightarrow 12x^2+21=11x^2-28 \\
\Leftrightarrow 12x^2-11x^2=-28-21 \\
\Leftrightarrow x^2 = -49 \\
\Leftrightarrow x^2 = \frac{-49}{1} < 0 \\
V = \varnothing \\ -----------------\)
- \(-3x^2+675=0 \\
\Leftrightarrow -3x^2 = -675 \\
\Leftrightarrow x^2 = \frac{-675}{-3}=225 \\
\Leftrightarrow x = 15 \vee x = -15 \\
V = \Big\{-15, 15 \Big\} \\ -----------------\)
- \(-5(-9x^2+5)=-(-48x^2-650) \\ \Leftrightarrow 45x^2-25=48x^2+650 \\
\Leftrightarrow 45x^2-48x^2=650+25 \\
\Leftrightarrow -3x^2 = 675 \\
\Leftrightarrow x^2 = \frac{675}{-3} < 0 \\
V = \varnothing \\ -----------------\)
- \(-2x^2-668=-6x^2+8 \\ \Leftrightarrow -2x^2+6x^2=8+668 \\
\Leftrightarrow 4x^2 = 676 \\
\Leftrightarrow x^2 = \frac{676}{4}=169 \\
\Leftrightarrow x = 13 \vee x = -13 \\
V = \Big\{-13, 13 \Big\} \\ -----------------\)
- \(-5(4x^2-3)=-(13x^2+48) \\ \Leftrightarrow -20x^2+15=-13x^2-48 \\
\Leftrightarrow -20x^2+13x^2=-48-15 \\
\Leftrightarrow -7x^2 = -63 \\
\Leftrightarrow x^2 = \frac{-63}{-7}=9 \\
\Leftrightarrow x = 3 \vee x = -3 \\
V = \Big\{-3, 3 \Big\} \\ -----------------\)
- \(7x^2-343=0 \\
\Leftrightarrow 7x^2 = 343 \\
\Leftrightarrow x^2 = \frac{343}{7}=49 \\
\Leftrightarrow x = 7 \vee x = -7 \\
V = \Big\{-7, 7 \Big\} \\ -----------------\)
- \(7x^2-1372=0 \\
\Leftrightarrow 7x^2 = 1372 \\
\Leftrightarrow x^2 = \frac{1372}{7}=196 \\
\Leftrightarrow x = 14 \vee x = -14 \\
V = \Big\{-14, 14 \Big\} \\ -----------------\)
- \(5(-8x^2-5)=-(35x^2+430) \\ \Leftrightarrow -40x^2-25=-35x^2-430 \\
\Leftrightarrow -40x^2+35x^2=-430+25 \\
\Leftrightarrow -5x^2 = -405 \\
\Leftrightarrow x^2 = \frac{-405}{-5}=81 \\
\Leftrightarrow x = 9 \vee x = -9 \\
V = \Big\{-9, 9 \Big\} \\ -----------------\)
- \(-5(-5x^2-4)=-(-24x^2-141) \\ \Leftrightarrow 25x^2+20=24x^2+141 \\
\Leftrightarrow 25x^2-24x^2=141-20 \\
\Leftrightarrow x^2 = 121 \\
\Leftrightarrow x^2 = \frac{121}{1}=121 \\
\Leftrightarrow x = 11 \vee x = -11 \\
V = \Big\{-11, 11 \Big\} \\ -----------------\)
- \(-2x^2-855=-7x^2-10 \\ \Leftrightarrow -2x^2+7x^2=-10+855 \\
\Leftrightarrow 5x^2 = 845 \\
\Leftrightarrow x^2 = \frac{845}{5}=169 \\
\Leftrightarrow x = 13 \vee x = -13 \\
V = \Big\{-13, 13 \Big\} \\ -----------------\)
- \(3(5x^2+8)=-(-23x^2-24) \\ \Leftrightarrow 15x^2+24=23x^2+24 \\
\Leftrightarrow 15x^2-23x^2=24-24 \\
\Leftrightarrow -8x^2 = 0 \\
\Leftrightarrow x^2 = \frac{0}{-8}\\
\Leftrightarrow x = 0 \\
V = \Big\{ 0 \Big\} \\ -----------------\)