<span> x = 3<span> x =(-12-√-4)/-2=6+i= 6.0000-1.0000i</span><span> x =(-12+√-4)/-2=6-i= 6.0000+1.000</span></span>
$500 was earned over 3 years
so, to find one year
500 ÷ 3 = $166.67
Interest for one year is $166.67
Interest rate for one year is 8%
8% = 166.67
1% = $20.83
100% = $2083.33
Principal amount is $2083.33
The given plane has normal vector

Scaling <em>n</em> by a real number <em>t</em> gives a set of vectors that span an entire line through the origin. Translating this line by adding the vector <2, 1, 1> makes it so that this line passes through the point (2, 1, 1). So this line has equation

This line passes through (2, 1, 1) when <em>t</em> = 0, and the line intersects with the plane when

which corresponds the point (3, -1, 1) (simply plug <em>t</em> = 1 into the coordinates of
).
So the distance between the plane and the point is the distance between the points (2, 1, 1) and (3, -1, 1):

Imaginary numbers
Imaginary numbers contain complex solutions (a +- bi)