Los de vierkantsvergelijking op zonder de discriminant te gebruiken
- \(3(-3x^2-10)=-(x^2+318)\)
- \(-8x^2+1568=0\)
- \(-4x^2-167=-3x^2+2\)
- \(2x^2+72=0\)
- \(-11x^2+1132=-6x^2+7\)
- \(7x^2+7=2x^2+7\)
- \(3(7x^2-7)=-(-13x^2+21)\)
- \(-8x^2+8=0\)
- \(2x^2-56=4x^2-6\)
- \(-4x^2+0=0\)
- \(-15x^2+347=-8x^2+4\)
- \(-4x^2+64=0\)
Los de vierkantsvergelijking op zonder de discriminant te gebruiken
Verbetersleutel
- \(3(-3x^2-10)=-(x^2+318) \\ \Leftrightarrow -9x^2-30=-x^2-318 \\
\Leftrightarrow -9x^2+x^2=-318+30 \\
\Leftrightarrow -8x^2 = -288 \\
\Leftrightarrow x^2 = \frac{-288}{-8}=36 \\
\Leftrightarrow x = 6 \vee x = -6 \\
V = \Big\{-6, 6 \Big\} \\ -----------------\)
- \(-8x^2+1568=0 \\
\Leftrightarrow -8x^2 = -1568 \\
\Leftrightarrow x^2 = \frac{-1568}{-8}=196 \\
\Leftrightarrow x = 14 \vee x = -14 \\
V = \Big\{-14, 14 \Big\} \\ -----------------\)
- \(-4x^2-167=-3x^2+2 \\ \Leftrightarrow -4x^2+3x^2=2+167 \\
\Leftrightarrow -x^2 = 169 \\
\Leftrightarrow x^2 = \frac{169}{-1} < 0 \\
V = \varnothing \\ -----------------\)
- \(2x^2+72=0 \\
\Leftrightarrow 2x^2 = -72 \\
\Leftrightarrow x^2 = \frac{-72}{2} < 0 \\
V = \varnothing \\ -----------------\)
- \(-11x^2+1132=-6x^2+7 \\ \Leftrightarrow -11x^2+6x^2=7-1132 \\
\Leftrightarrow -5x^2 = -1125 \\
\Leftrightarrow x^2 = \frac{-1125}{-5}=225 \\
\Leftrightarrow x = 15 \vee x = -15 \\
V = \Big\{-15, 15 \Big\} \\ -----------------\)
- \(7x^2+7=2x^2+7 \\ \Leftrightarrow 7x^2-2x^2=7-7 \\
\Leftrightarrow 5x^2 = 0 \\
\Leftrightarrow x^2 = \frac{0}{5}\\
\Leftrightarrow x = 0 \\
V = \Big\{ 0 \Big\} \\ -----------------\)
- \(3(7x^2-7)=-(-13x^2+21) \\ \Leftrightarrow 21x^2-21=13x^2-21 \\
\Leftrightarrow 21x^2-13x^2=-21+21 \\
\Leftrightarrow 8x^2 = 0 \\
\Leftrightarrow x^2 = \frac{0}{8}\\
\Leftrightarrow x = 0 \\
V = \Big\{ 0 \Big\} \\ -----------------\)
- \(-8x^2+8=0 \\
\Leftrightarrow -8x^2 = -8 \\
\Leftrightarrow x^2 = \frac{-8}{-8}=1 \\
\Leftrightarrow x = 1 \vee x = -1 \\
V = \Big\{-1, 1 \Big\} \\ -----------------\)
- \(2x^2-56=4x^2-6 \\ \Leftrightarrow 2x^2-4x^2=-6+56 \\
\Leftrightarrow -2x^2 = 50 \\
\Leftrightarrow x^2 = \frac{50}{-2} < 0 \\
V = \varnothing \\ -----------------\)
- \(-4x^2+0=0 \\
\Leftrightarrow -4x^2 = 0 \\
\Leftrightarrow x^2 = \frac{0}{-4}\\
\Leftrightarrow x = 0 \\
V = \Big\{ 0 \Big\} \\ -----------------\)
- \(-15x^2+347=-8x^2+4 \\ \Leftrightarrow -15x^2+8x^2=4-347 \\
\Leftrightarrow -7x^2 = -343 \\
\Leftrightarrow x^2 = \frac{-343}{-7}=49 \\
\Leftrightarrow x = 7 \vee x = -7 \\
V = \Big\{-7, 7 \Big\} \\ -----------------\)
- \(-4x^2+64=0 \\
\Leftrightarrow -4x^2 = -64 \\
\Leftrightarrow x^2 = \frac{-64}{-4}=16 \\
\Leftrightarrow x = 4 \vee x = -4 \\
V = \Big\{-4, 4 \Big\} \\ -----------------\)