Los de vierkantsvergelijking op zonder de discriminant te gebruiken
- \(2(-5x^2+4)=-(6x^2-44)\)
- \(3(-3x^2-2)=-(11x^2+6)\)
- \(5(9x^2-3)=-(-42x^2-660)\)
- \(-7x^2+67=-5x^2-5\)
- \(-13x^2-140=-9x^2+4\)
- \(-x^2-100=0\)
- \(4(-8x^2+9)=-(28x^2+0)\)
- \(2(-4x^2+3)=-(2x^2+858)\)
- \(x^2+49=0\)
- \(2x^2+450=0\)
- \(2(-10x^2-6)=-(19x^2-109)\)
- \(3x^2-718=9x^2+8\)
Los de vierkantsvergelijking op zonder de discriminant te gebruiken
Verbetersleutel
- \(2(-5x^2+4)=-(6x^2-44) \\ \Leftrightarrow -10x^2+8=-6x^2+44 \\
\Leftrightarrow -10x^2+6x^2=44-8 \\
\Leftrightarrow -4x^2 = 36 \\
\Leftrightarrow x^2 = \frac{36}{-4} < 0 \\
V = \varnothing \\ -----------------\)
- \(3(-3x^2-2)=-(11x^2+6) \\ \Leftrightarrow -9x^2-6=-11x^2-6 \\
\Leftrightarrow -9x^2+11x^2=-6+6 \\
\Leftrightarrow 2x^2 = 0 \\
\Leftrightarrow x^2 = \frac{0}{2}\\
\Leftrightarrow x = 0 \\
V = \Big\{ 0 \Big\} \\ -----------------\)
- \(5(9x^2-3)=-(-42x^2-660) \\ \Leftrightarrow 45x^2-15=42x^2+660 \\
\Leftrightarrow 45x^2-42x^2=660+15 \\
\Leftrightarrow 3x^2 = 675 \\
\Leftrightarrow x^2 = \frac{675}{3}=225 \\
\Leftrightarrow x = 15 \vee x = -15 \\
V = \Big\{-15, 15 \Big\} \\ -----------------\)
- \(-7x^2+67=-5x^2-5 \\ \Leftrightarrow -7x^2+5x^2=-5-67 \\
\Leftrightarrow -2x^2 = -72 \\
\Leftrightarrow x^2 = \frac{-72}{-2}=36 \\
\Leftrightarrow x = 6 \vee x = -6 \\
V = \Big\{-6, 6 \Big\} \\ -----------------\)
- \(-13x^2-140=-9x^2+4 \\ \Leftrightarrow -13x^2+9x^2=4+140 \\
\Leftrightarrow -4x^2 = 144 \\
\Leftrightarrow x^2 = \frac{144}{-4} < 0 \\
V = \varnothing \\ -----------------\)
- \(-x^2-100=0 \\
\Leftrightarrow -x^2 = 100 \\
\Leftrightarrow x^2 = \frac{100}{-1} < 0 \\
V = \varnothing \\ -----------------\)
- \(4(-8x^2+9)=-(28x^2+0) \\ \Leftrightarrow -32x^2+36=-28x^2+0 \\
\Leftrightarrow -32x^2+28x^2=0-36 \\
\Leftrightarrow -4x^2 = -36 \\
\Leftrightarrow x^2 = \frac{-36}{-4}=9 \\
\Leftrightarrow x = 3 \vee x = -3 \\
V = \Big\{-3, 3 \Big\} \\ -----------------\)
- \(2(-4x^2+3)=-(2x^2+858) \\ \Leftrightarrow -8x^2+6=-2x^2-858 \\
\Leftrightarrow -8x^2+2x^2=-858-6 \\
\Leftrightarrow -6x^2 = -864 \\
\Leftrightarrow x^2 = \frac{-864}{-6}=144 \\
\Leftrightarrow x = 12 \vee x = -12 \\
V = \Big\{-12, 12 \Big\} \\ -----------------\)
- \(x^2+49=0 \\
\Leftrightarrow x^2 = -49 \\
\Leftrightarrow x^2 = \frac{-49}{1} < 0 \\
V = \varnothing \\ -----------------\)
- \(2x^2+450=0 \\
\Leftrightarrow 2x^2 = -450 \\
\Leftrightarrow x^2 = \frac{-450}{2} < 0 \\
V = \varnothing \\ -----------------\)
- \(2(-10x^2-6)=-(19x^2-109) \\ \Leftrightarrow -20x^2-12=-19x^2+109 \\
\Leftrightarrow -20x^2+19x^2=109+12 \\
\Leftrightarrow -x^2 = 121 \\
\Leftrightarrow x^2 = \frac{121}{-1} < 0 \\
V = \varnothing \\ -----------------\)
- \(3x^2-718=9x^2+8 \\ \Leftrightarrow 3x^2-9x^2=8+718 \\
\Leftrightarrow -6x^2 = 726 \\
\Leftrightarrow x^2 = \frac{726}{-6} < 0 \\
V = \varnothing \\ -----------------\)