Question
Solve the following equations for x and give, in each case, your answer correct to 3 decimal places
$3x^2 – 12x – 1 =0$
$3x^2 – 12x – 1 =0$
✓
Answer
$3 x^2-12 x-1=0$
Here $a= 3, b = -12$ and $c = -1$
$x=\frac{-b \pm \sqrt{b^2-4 a c}}{2 a}$
$=\frac{-(-12) \pm \sqrt{(-12)^2-4(3)(-1)}}{2(3)}$
$=\frac{12 \pm \sqrt{156}}{6}$
$=\frac{12 \pm 12.489}{6}$
$=4.082$ and -0.082
Here $a= 3, b = -12$ and $c = -1$
$x=\frac{-b \pm \sqrt{b^2-4 a c}}{2 a}$
$=\frac{-(-12) \pm \sqrt{(-12)^2-4(3)(-1)}}{2(3)}$
$=\frac{12 \pm \sqrt{156}}{6}$
$=\frac{12 \pm 12.489}{6}$
$=4.082$ and -0.082
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