Question

If 25x square minus mx + 4,then what is value of m

Answer 1

$25 {x}^{2} - mx \: + 4$
${5x}^{2} - 2.5x.2 + {2}^{2}$
${5x}^{2} - 20x + {4}^{2}$
so, m = -20

​