Question

помогите номер 11!!!!!!!!!!!!!!!

Answer 1

${(z - 5)}^{2} - (z - 5)(z + 5) + 10z = \\ = (z - 5)(z - 5 - z - 5) + 10z = \\ = - 10(z - 5) + 10z = \\ = - 10z + 50 + 10z = 50$

или

${(z - 5)}^{2} - (z - 5)(z + 5) + 10z = \\ = {z}^{2} - 10z + 25 - ( {z}^{2} - 25) + 10z = \\ = {z}^{2} + 25 - {z}^{2} + 25 = 50$