Question

(2x-3)²+(x-5)(x+5)-(x+4)²:

Answer 1

(2x-3) . (2x-3) + (x-5) . (x+5) - (x+4) . (x+4)
4x -6x -6x +9 +x² +5x -5x +25 -x² -4x +4x +16

*cortando o que se pode*
sobrou:
4x -6x -6x +9 +25 +16
-12x +4x +50
-8x +50 
-8x +50 = 0
50 = 8x
x = $\frac{50}{8}$
x = 6,25

Answer 2

(2x-3)²+(x-5)(x+5)-(x+4)²

(2x - 3).(2x - 3) + (x² + 5x - 5x - 25) - (x + 4).(x + 4)

4x² - 6x - 6x + 9 + x² + 5x - 5x - 25 - (x² + 4x + 4x + 16)

4x² - 6x - 6x + 9 + x² + 5x - 5x - 25 - x² - 4x - 4x - 16

4x² + x² - x² - 6x - 6x - 5x - 4x - 4x  + 5x + 9 - 25 - 16

5x² - x²  - 25x + 5x + 9 - 41

4x²  - 20x - 32

4.(x² - 5x - 8)