3х² + 9х = 0
3х(х + 3) = 0
3х = 0 или х + 3 = 0
х = 0 х = -3
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2х² - 18 = 0
2х² = 18
х² = 18/2
х = +-√9
х1 = 3 х2 = - 3
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4х² = 0
х² = 0
х = 0
x см и у см - стороны параллелограма, (x<15, y<24)