SOLUTION: Which of the following expressions is equal to -3x^2-27
A ) (-3x-3i)(x-9i)
B ) (-3x-9i)(x+3i)
C ) (-3x+3i)(x+9i)
D ) (-3X+9i)(x+3i)
i know i have to factor (i think) to solve
Question 1082119: Which of the following expressions is equal to -3x^2-27
A ) (-3x-3i)(x-9i)
B ) (-3x-9i)(x+3i)
C ) (-3x+3i)(x+9i)
D ) (-3X+9i)(x+3i)
i know i have to factor (i think) to solve it but i'm having trouble when it comes to getting the final form ( cant think of the right term) Found 3 solutions by Boreal, math_helper, MathLover1:Answer by Boreal(15235) (Show Source):
You can put this solution on YOUR website! it is -3(x^2+9)=or -3(x+/-3i)=-3(x+3i)(x-3i)
-3x+9i could be one factor with (x+3i), -3x-9i could be another with (x-3i).
D works.
-3(x-3i)(x+3i)
You can put this solution on YOUR website! Three criteria must be met:
1) the factors must multiply to give a -3x^2 terms (all of therm do)
2) the factors must multiply such that the xi terms cancel (NOT all of them do)
3) the factors must multiply to give -27 (= +27i^2 because i^2 = -1) (NOT all of them do)
I'll add that A) is NOT correct because —> which has a term.
You can put this solution on YOUR website! ........here we have the sum of squares and we can write it as the difference of squares if we write as , and we know that ; so, we have or now factor it as the difference of the squares and you have
plug it in: ....multiply
answer:
D )
