A. 4x² - 5x = 0
x(4x - 5) = 0
<img src="https://tex.z-dn.net/?f=%20x_%7B1%7D%20" />→x = 0
<img src="https://tex.z-dn.net/?f=%20x_%7B1%7D%20" /> = 0
<img src="https://tex.z-dn.net/?f=%20x_%7B2%7D%20" />→ 4x - 5 = 0
<img src="https://tex.z-dn.net/?f=%20x_%7B2%7D%20" />→ x = <img src="https://tex.z-dn.net/?f=%20%5Cfrac%7B5%7D%7B4%7D%20" />
<img src="https://tex.z-dn.net/?f=%20x_%7B2%7D%20" /> = <img src="https://tex.z-dn.net/?f=%20%5Cfrac%7B5%7D%7B4%7D%20" />
b.
3x² + 2x = 0
x(3x + 2) = 0
<img src="https://tex.z-dn.net/?f=%20x_%7B1%7D%20" />→x = 0
<img src="https://tex.z-dn.net/?f=%20x_%7B1%7D%20" /> = 0
<img src="https://tex.z-dn.net/?f=%20x_%7B2%7D%20" />→3x + 2 = 0
[img = 10]→ x = [img = 11]
[img = 12] = [img = 13]
c.
X² - 70 = 155
[img = 14] - 70 - 155 = 0
[img = 15] - 225 = 0
(x + 15)(x - 15) = 0
[img = 16]→x + 15 = 0
[img = 17]→ x = - 15
[img = 18] = - 15
[img = 19]→ x - 15 = 0
[img = 20]→ x = 15
[img = 21] = 15
d.
[img = 22]x² + [img = 23]x = 0
x([img = 24]x + [img = 25]) = 0
[img = 26]→x = 0
[img = 27] = 0
[img = 28]→ 4 / 5x + 5 / 3 = 0
[img = 29]→ 4 / 5x = - 5 / 3
[img = 30]→ x = [img = 31]
[img = 32]→ x = [img = 33]
[img = 34] = [img = 35]
e.
2 / 3x² - 3 / 2x = 0
x(2 / 3x - 3 / 2) = 0
[img = 36]→x = 0
[img = 37]→ 0
[img = 38]→ 2 / 3x - 3 / 2 = 0
[img = 39]→ 2 / 3x = 3 / 2
[img = 40]→ x = [img = 41]
[img = 42]→ x = [img = 43]
[img = 44] = [img = 45]
f.
X² + 80 = 980
x² + 80 - 980 = 0
x² - 900 = 0
(x + 30)(x - 30) = 0
[img = 46]→x + 30 = 0
[img = 47]→ x = - 30
[img = 48] = - 30
[img = 49]→ x - 30 = 0
[img = 50]→ x = 30
[img = 51] = 30.