Question

22) 4 + x ( x - 4)=x | 23) x (x + 3)-40=0 |

Answer 1

22) 4 + x ( x - 4) = x *[Distributiva]*
4 + x² - 4x = x *[Organização dos termos]*
x² - 4x - x + 4 = 0
x² -5x + 4 = 0 *[Bháskara]*
delta = -5² - 4. 1 . 4
delta = 25 - 16
delta = 9
(-5 +- √9)/2.1
(-5 +- 3)/2
x1 = -2/2 = -1
x2 = -8/2 = -4

23) x (x+3) - 40 = 0 *[Distributiva]*
x² + 3x - 40 = 0 *[Bháskara]*
delta = 3² - 4 . 1 . -40
delta = 9 + 160
delta = 169
(-3 +- √169)/2.1
(-3 +- 13)/2
x1 = 10/2 = 5
x2 = -16/2 = -8

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