Question

4x(4xsquare+5)+5(4xsquare+5)

Answer 1

16x^2+20+20x^2+25
=36x^2+45
it's the answer

Answer 2

Hello Mate!

$4x(4x^2 + 5) + 5(4x^2 + 5) = 0\\ (4x + 5)(4x^2 + 5) = 0 \\ 4x + 5 = 0 \\ x = \frac{ - 5}{4}$

OR

4x^2 + 5 = 0
x^2 = -5/4
x = _/-5 / 2


Hope it helps☺!