Using the given zero, find one other zero of f(x). 2 - 4i is a zero of f(x).= x4 - 4x3 + 21x2 - 4x + 20 a.1 + i b.1 c.1 - i d.2 + 4i

2 + 4i

Complex roots of polynomials with real coefficients come in conjugate pairs. The conjugate of a complex number has the same real part, but an imaginary part with opposite sign. (It is sometimes indicated using an asterisk.)

(2 - 4i)* = 2 + 4i . . . . . . the other complex root of this conjugate pair

Factoring out (x² -4x +20) from f(x) gives (x² +1). Its roots are ±i, so are not on the list of answer choices.

-3

step-by-step explanation:

a drawing really does here:

so i draw the horizontal line y=2 and the vertical line x=-2 at this intersection i put b (this is where my right angle is going to be).   so point b is at (-2,2).   point a is 5 units long and is also on y=2 so this point has to be (3,2) or (-7,2) -doesn't matter i will go with (3,2).

now we know c is at (-2,y) we don't know the y yet bet we know that c is on x=-2.

we have the area of the triangle is .5bh=12.5

we know the base length is 5 (ab)

we have the height is (2-y) if you look at your

plug in

.5(5)(2-y)=12.5

solve for y to get the y-coordinate for c

2.5(2-y)=12.5

divide both sides by 2.5 giving:

2-y=5

now subtract 2 on both sides

-y=3

y=-3

mx+89b(-98)nb

step-by-step explanation: