Question

equação do 2° grau
ײ+2.9x+9²=0​

Answer 1

${x}^{2} + 2 \times 9x + {9}^{2} = 0 \\ {x}^{2} + 18x + 81 = 0 \\ \\ \frac{ - b + - \sqrt{ {b}^{2} - 4ac} }{2a} \\ \frac{ - 18 + - \sqrt{324 - 4 \times 1 \times 81} }{2} \\ \frac{ - 18 + - \sqrt{324 - 324} }{2} \\ \frac{ - 18 + - 0}{2} = \frac{ - 18}{2} = - 9$