Los de vierkantsvergelijking op zonder de discriminant te gebruiken
- \(2(-10x^2+2)=-(18x^2-132)\)
- \(-7x^2-96=-6x^2+4\)
- \(5(6x^2+5)=-(-26x^2-29)\)
- \(-3x^2+675=0\)
- \(5x^2+320=0\)
- \(-x^2+49=0\)
- \(-6x^2-216=0\)
- \(3(7x^2+8)=-(-18x^2-51)\)
- \(-2x^2-119=6x^2+9\)
- \(7x^2-28=0\)
- \(-2x^2+392=0\)
- \(-3(-10x^2-10)=-(-38x^2+258)\)
Los de vierkantsvergelijking op zonder de discriminant te gebruiken
Verbetersleutel
- \(2(-10x^2+2)=-(18x^2-132) \\ \Leftrightarrow -20x^2+4=-18x^2+132 \\
\Leftrightarrow -20x^2+18x^2=132-4 \\
\Leftrightarrow -2x^2 = 128 \\
\Leftrightarrow x^2 = \frac{128}{-2} < 0 \\
V = \varnothing \\ -----------------\)
- \(-7x^2-96=-6x^2+4 \\ \Leftrightarrow -7x^2+6x^2=4+96 \\
\Leftrightarrow -x^2 = 100 \\
\Leftrightarrow x^2 = \frac{100}{-1} < 0 \\
V = \varnothing \\ -----------------\)
- \(5(6x^2+5)=-(-26x^2-29) \\ \Leftrightarrow 30x^2+25=26x^2+29 \\
\Leftrightarrow 30x^2-26x^2=29-25 \\
\Leftrightarrow 4x^2 = 4 \\
\Leftrightarrow x^2 = \frac{4}{4}=1 \\
\Leftrightarrow x = 1 \vee x = -1 \\
V = \Big\{-1, 1 \Big\} \\ -----------------\)
- \(-3x^2+675=0 \\
\Leftrightarrow -3x^2 = -675 \\
\Leftrightarrow x^2 = \frac{-675}{-3}=225 \\
\Leftrightarrow x = 15 \vee x = -15 \\
V = \Big\{-15, 15 \Big\} \\ -----------------\)
- \(5x^2+320=0 \\
\Leftrightarrow 5x^2 = -320 \\
\Leftrightarrow x^2 = \frac{-320}{5} < 0 \\
V = \varnothing \\ -----------------\)
- \(-x^2+49=0 \\
\Leftrightarrow -x^2 = -49 \\
\Leftrightarrow x^2 = \frac{-49}{-1}=49 \\
\Leftrightarrow x = 7 \vee x = -7 \\
V = \Big\{-7, 7 \Big\} \\ -----------------\)
- \(-6x^2-216=0 \\
\Leftrightarrow -6x^2 = 216 \\
\Leftrightarrow x^2 = \frac{216}{-6} < 0 \\
V = \varnothing \\ -----------------\)
- \(3(7x^2+8)=-(-18x^2-51) \\ \Leftrightarrow 21x^2+24=18x^2+51 \\
\Leftrightarrow 21x^2-18x^2=51-24 \\
\Leftrightarrow 3x^2 = 27 \\
\Leftrightarrow x^2 = \frac{27}{3}=9 \\
\Leftrightarrow x = 3 \vee x = -3 \\
V = \Big\{-3, 3 \Big\} \\ -----------------\)
- \(-2x^2-119=6x^2+9 \\ \Leftrightarrow -2x^2-6x^2=9+119 \\
\Leftrightarrow -8x^2 = 128 \\
\Leftrightarrow x^2 = \frac{128}{-8} < 0 \\
V = \varnothing \\ -----------------\)
- \(7x^2-28=0 \\
\Leftrightarrow 7x^2 = 28 \\
\Leftrightarrow x^2 = \frac{28}{7}=4 \\
\Leftrightarrow x = 2 \vee x = -2 \\
V = \Big\{-2, 2 \Big\} \\ -----------------\)
- \(-2x^2+392=0 \\
\Leftrightarrow -2x^2 = -392 \\
\Leftrightarrow x^2 = \frac{-392}{-2}=196 \\
\Leftrightarrow x = 14 \vee x = -14 \\
V = \Big\{-14, 14 \Big\} \\ -----------------\)
- \(-3(-10x^2-10)=-(-38x^2+258) \\ \Leftrightarrow 30x^2+30=38x^2-258 \\
\Leftrightarrow 30x^2-38x^2=-258-30 \\
\Leftrightarrow -8x^2 = -288 \\
\Leftrightarrow x^2 = \frac{-288}{-8}=36 \\
\Leftrightarrow x = 6 \vee x = -6 \\
V = \Big\{-6, 6 \Big\} \\ -----------------\)