Question

factorise m²+18m-84​

Answer 1

${m}^{2} + 18m - 84 = 0 \\ \\ a = 1 \\ b = + 18 \\ c = - 84 \\ \\ \delta = \frac{ {b}^{2} - 4ac }{2a } \\ \\ \: \: \: = \: \frac{{18}^{2} - 4(1)( - 84)}{2(1)} \\ \: \: \: \\ \: \: \: = \frac{324 + 336}{2} \\ \\ \: \: \: = \frac{660}{2} \\ \\ \: \: \: = 330 \\ \\ \: \: \: m = \frac{ - b \ \pm \: \sqrt{ \delta} }{2a} \\ \\ \: \: \: \: m = \frac{ - 18 \pm \: \sqrt{330} }{2} \\ \\ \: \: \: \: m = - 9 + \frac{ \sqrt{330} }{2} \: \: \: \: or \: \: \: m = - 9 - \frac{ \sqrt{330} }{2} \\ \\ hope \: it \: helps \: you$