Tolong bantu

<p>x² - 3x - 18 = 0</p><p>a = 1, b = -3 dan c = -18</p><p>&nbsp;</p><p>x₁² + x₂² = (x₁ + x₂)² - 2x_1. x₂</p><p>_{&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp;} &nbsp;= (-b/a)² - 2(c/a)</p><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; = (-(-3)/1)² - 2(-18/1)</p><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; = 3² + 36</p><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; = 9 + 36</p><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; = <strong>45</strong></p>