Question

Write a quadratic equation in standard form if the zeros are ±7i.

Answer 1

(x+7i)(x-7i)

Answer 2

Zero means x=that.
x=7i
x=-7i
To make these into factors, we get them equal to 0.
x+7i=0
x-7i=0
We can put these into an equation now.
(x+7i)(x-7i)=0
Expansion of complex conjugates is easy: (a+bi)(a-bi)=a^2+b^2
x^2+49=0

Answer 3

If you want the work for expansion:
(x+7i)(x-7i)
x(x-7i) +7i(x-7i)
x^2-7xi +7xi -7i*7i
x^2+0xi-49i^2
i^2=sqrt(-1)^2=-1, so
x^2-49*-1
x^2+49

Answer 4

Finally get this now, thanks so much! This was a big help! =)