Verified Answer :
must use quadratic formula (basically completing the square)
so
for an equation
ax^2+bx+c=0
x=\(\frac{-b+/- \sqrt{b^2-4ac} }{2a}\)
ax^2+bx+c=0
-3x^2-4x-4=0
a=-3
b=-4
c=-4
x=\(\frac{-(-4)+/- \sqrt{(-4)^2-4(-3)(-4)} }{2(-4)}\)
x=\(\frac{4+/- \sqrt{16-48} }{-8}\)
x=\(\frac{4+/- \sqrt{-32} }{-8}\)
x=\(\frac{4+/- (\sqrt{-1})(\sqrt{32}) }{-8}\)
x=\(\frac{4+/- (i)(\sqrt{(4)(4)(2)}) }{-8}\)
x=\(\frac{4+/- (i)(4\sqrt{2}) }{-8}\)
x=\(\frac{4+/- 4i\sqrt{2} }{-8}\)
x=\(\frac{1+/- i\sqrt{2} }{-2}\)
x=\(\frac{1+ i\sqrt{2} }{-2}\) or \(\frac{1- i\sqrt{2} }{-2}\)
or
x=\(\frac{-1- i\sqrt{2} }{2}\) or \(\frac{-1+ i\sqrt{2} }{2}\)
Answer:
\(x1=\frac{-2(+)2i\sqrt{2}} {3}\)
\(x2=\frac{-2(-)2i\sqrt{2}} {3}\)
Step-by-step explanation:
we have
\(-3x^{2} -4x-4=0\)
Rewrite (Multiply by \(-1\) both sides)
\(3x^{2}+4x+4=0\)
The formula to solve a quadratic equation of the form \(ax^{2} +bx+c=0\) is equal to
\(x=\frac{-b(+/-)\sqrt{b^{2}-4ac}} {2a}\)
in this problem we have
\(3x^{2}+4x+4=0\)
so
\(a=3\\b=4\\c=4\)
substitute
\(x=\frac{-4(+/-)\sqrt{4^{2}-4(3)(4)}} {2(3)}\)
\(x=\frac{-4(+/-)\sqrt{-32}} {6}\)
remember that
\(i=\sqrt{-1}\)
\(x=\frac{-4(+/-)4i\sqrt{2}} {6}\)
Simplify
\(x=\frac{-2(+/-)2i\sqrt{2}} {3}\)
\(x1=\frac{-2(+)2i\sqrt{2}} {3}\)
\(x2=\frac{-2(-)2i\sqrt{2}} {3}\)