Question

Solve the following quadratic equations by usingcomleting the square method.×^+8×-9=0

Answer 1

Step-by-step explanation:

${x}^{2} + 8x - 9 = 0 \\ = > {x}^{2} + 8x = 9 \\ by \: multipling \: 4a \: into \: all \: polynomials \: we \: get \\ 4( {x}^{2} + 8x) = 9 \times 4 \\ = > {4x}^{2} + 32x = 36 \\ = > {(2x)}^{2} + 2 \times 2x \times 8 = 9 \\ = > {2x}^{2} + 2 \times 2x \times 8 + {8}^{2} = 9 + {8}^{2} \\ = > (2x + 8) {}^{2} = 9 + 64 = 73 \\ = > 2x + 8 = + - \sqrt{73} \\ = 2x = + - \sqrt{73} - 8 \\ = > x = \frac{ \sqrt{73} - 8 }{2} \: or \: \frac{ - \sqrt{73 } - 8}{2}$