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Solve $x^{2} - 9 x + 18 = 0$ by completing the square; the roots are:

Class 10Completing the SquareQuadratic Equations

A3 and 6
B2 and 9
C1 and 18
D-3 and -6

Step-by-Step Solution

x^{2} - 9 x = - 18

, add

\frac{81}{4} : (x - \frac{9}{2})^{2} = \frac{81}{4} - 18 = \frac{9}{4}, x - \frac{9}{2} = + / - \frac{3}{2}, x = 6

or

x = 3

.

Answer: A) 3 and 6

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