Question

18x elevado a 2 +10x=0
2x elevado a 2 -7x=0
36x elevado a 2 -81=0

Answer 1

18x² + 10x = 0
 2x (9x + 5) = 0

2x = 0 --> x = 0
9x + 5 = 0 --> 9x = -5 --> x = -5/9
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2x² - 7x = 0
x (2x - 7) = 0

x = 0
2x - 7 =0 --> 2x = 7 ---> x = 7/2

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36x² - 81 = 0
36x² = 81
    x² = 81/36 ---> x = √81/36 ---> x = 9/6 = 3/2