Solve the equation by factoring.

x = 5i   x =-5i

Step-by-step explanation:

x^2+25=0

Rewriting

x^2 - (-25)=0

Writing as the difference of squares

a^2 - b^2= (a-b) (a+b)

where a = x and b = (sqrt(-25)) =±5i

( x-5i) ( x+5i) =0

Using the zero product property

x-5i =0    x+5i =0

x = 5i   x =-5i

x = 5i

x = -5i

Step-by-step explanation:

x² + 25 = 0

x² = 0 - 25

x² = -25

x = √-25

x = 5i

hello from mrbilldoesmath!

answer:

25x^2 + 90x + 84

discussion:

mn(x) = m(n(x)) = m( 5x + 9) =

(5x + 9)^2 + 3 =>

25x^2 + 90x + 9^2 + 3 =

25x^2 + 90x + 84                 (as 9^2 = 9*9 = 81)

which is the second choice

regards,  

mrb

p.s.   i'll be on vacation from friday, dec 22 to jan 2, 2019. have a great new year!