<span>17*cos 86/sin 4=17*cos(90-4)/sin 4=17*sin 4/sin 4=17 вот так кажется незнаю я неочень разбераюсь</span>
16/(√7 - √23) = 16*(√7 + √23) / ((√7 - √23)(√7 + √23)) =
= 16*(√7 + √23) / (7 - 23) = - (√7 + √23) = -√7 -√23
46/√23 = 46√23/(√23 * √23) = (46√23)/23 = 2√23
9x^2 - 4 = 0
9x^2 = 4
x^2 = 4/9
x = ± √(4/9)
x = ± 2/3
2y(n-m)+(m-n)=2y(n-m)-(n-m)=(n-m)(2y-1)