Los de vierkantsvergelijking op zonder de discriminant te gebruiken
- \(3(-7x^2-7)=-(15x^2+237)\)
- \(-2x^2+98=0\)
- \(-3(-7x^2-7)=-(-18x^2-48)\)
- \(7x^2-343=0\)
- \(2(-6x^2+2)=-(10x^2+4)\)
- \(-9x^2+906=-5x^2+6\)
- \(-2x^2+50=0\)
- \(7x^2-847=0\)
- \(-3(10x^2+6)=-(26x^2-178)\)
- \(-2(4x^2-4)=-(14x^2+1006)\)
- \(5x^2+0=0\)
- \(7x^2+7=10x^2+7\)
Los de vierkantsvergelijking op zonder de discriminant te gebruiken
Verbetersleutel
- \(3(-7x^2-7)=-(15x^2+237) \\ \Leftrightarrow -21x^2-21=-15x^2-237 \\
\Leftrightarrow -21x^2+15x^2=-237+21 \\
\Leftrightarrow -6x^2 = -216 \\
\Leftrightarrow x^2 = \frac{-216}{-6}=36 \\
\Leftrightarrow x = 6 \vee x = -6 \\
V = \Big\{-6, 6 \Big\} \\ -----------------\)
- \(-2x^2+98=0 \\
\Leftrightarrow -2x^2 = -98 \\
\Leftrightarrow x^2 = \frac{-98}{-2}=49 \\
\Leftrightarrow x = 7 \vee x = -7 \\
V = \Big\{-7, 7 \Big\} \\ -----------------\)
- \(-3(-7x^2-7)=-(-18x^2-48) \\ \Leftrightarrow 21x^2+21=18x^2+48 \\
\Leftrightarrow 21x^2-18x^2=48-21 \\
\Leftrightarrow 3x^2 = 27 \\
\Leftrightarrow x^2 = \frac{27}{3}=9 \\
\Leftrightarrow x = 3 \vee x = -3 \\
V = \Big\{-3, 3 \Big\} \\ -----------------\)
- \(7x^2-343=0 \\
\Leftrightarrow 7x^2 = 343 \\
\Leftrightarrow x^2 = \frac{343}{7}=49 \\
\Leftrightarrow x = 7 \vee x = -7 \\
V = \Big\{-7, 7 \Big\} \\ -----------------\)
- \(2(-6x^2+2)=-(10x^2+4) \\ \Leftrightarrow -12x^2+4=-10x^2-4 \\
\Leftrightarrow -12x^2+10x^2=-4-4 \\
\Leftrightarrow -2x^2 = -8 \\
\Leftrightarrow x^2 = \frac{-8}{-2}=4 \\
\Leftrightarrow x = 2 \vee x = -2 \\
V = \Big\{-2, 2 \Big\} \\ -----------------\)
- \(-9x^2+906=-5x^2+6 \\ \Leftrightarrow -9x^2+5x^2=6-906 \\
\Leftrightarrow -4x^2 = -900 \\
\Leftrightarrow x^2 = \frac{-900}{-4}=225 \\
\Leftrightarrow x = 15 \vee x = -15 \\
V = \Big\{-15, 15 \Big\} \\ -----------------\)
- \(-2x^2+50=0 \\
\Leftrightarrow -2x^2 = -50 \\
\Leftrightarrow x^2 = \frac{-50}{-2}=25 \\
\Leftrightarrow x = 5 \vee x = -5 \\
V = \Big\{-5, 5 \Big\} \\ -----------------\)
- \(7x^2-847=0 \\
\Leftrightarrow 7x^2 = 847 \\
\Leftrightarrow x^2 = \frac{847}{7}=121 \\
\Leftrightarrow x = 11 \vee x = -11 \\
V = \Big\{-11, 11 \Big\} \\ -----------------\)
- \(-3(10x^2+6)=-(26x^2-178) \\ \Leftrightarrow -30x^2-18=-26x^2+178 \\
\Leftrightarrow -30x^2+26x^2=178+18 \\
\Leftrightarrow -4x^2 = 196 \\
\Leftrightarrow x^2 = \frac{196}{-4} < 0 \\
V = \varnothing \\ -----------------\)
- \(-2(4x^2-4)=-(14x^2+1006) \\ \Leftrightarrow -8x^2+8=-14x^2-1006 \\
\Leftrightarrow -8x^2+14x^2=-1006-8 \\
\Leftrightarrow 6x^2 = -1014 \\
\Leftrightarrow x^2 = \frac{-1014}{6} < 0 \\
V = \varnothing \\ -----------------\)
- \(5x^2+0=0 \\
\Leftrightarrow 5x^2 = 0 \\
\Leftrightarrow x^2 = \frac{0}{5}\\
\Leftrightarrow x = 0 \\
V = \Big\{ 0 \Big\} \\ -----------------\)
- \(7x^2+7=10x^2+7 \\ \Leftrightarrow 7x^2-10x^2=7-7 \\
\Leftrightarrow -3x^2 = 0 \\
\Leftrightarrow x^2 = \frac{0}{-3}\\
\Leftrightarrow x = 0 \\
V = \Big\{ 0 \Big\} \\ -----------------\)