Solve x^2 + 4x + 8 = 0.

Question

asked Mar 12, 2019 190k views

2 Answers

SopheakVirak · Answer 1 · 2019-03-16T19:05:02+0000

Answer:

The solution to the quadratic equations are:

$x=-2+2i,\:x=-2-2i$

Explanation:

Consider the provided quadratic equation.

x^2 + 4x + 8 = 0

$\mathrm{For\:a\:quadratic\:equation\:of\:the\:form\:}ax^2+bx+c=0\mathrm{\:the\:solutions\:are\:}\\x_(1,\:2)=(-b\pm √(b^2-4ac))/(2a)$

Substitute a=1, b=4 and c=8 in above formula.

$x_(1,\:2)=(-4\pm √(4^2-4\cdot \:1\cdot \:8))/(2\cdot \:1)$

$x_(1,\:2)=(-4\pm √(16-32))/(2)$

$x_(1,\:2)=(-4\pm √(-16))/(2)$

$x_(1,\:2)=(-4\pm 4i)/(2)$

$x_(1,\:2)=-2\pm 2i$

Hence, the solution to the quadratic equations are:

$x=-2+2i,\:x=-2-2i$