ответ:2
Пошаговое объяснение:2х-16=-5х-30
2х+5х=16-30
7х=-14
х=-14÷7
х=-2
tg a = sin a / cos a
ctg a = cos a / sin a ctg a = 1/ tg a
(sin a)^2 + (cos a)^2 = 1 sin a = корень(1- (cos a)^2)
1) cos a = 5/13
sin a = корень(1-25/169) = корень(144/169) = 12/13
tg a = 12/13 : 5/13 = 12/13 * 13/5 = 12/5 = 2.4
ctg a = 1 : 12/5 = 5/12
2) cos a = 15/17
sin a = корень(1-225/289) = корень(64/289) = 8/17
tg a = 8/17 : 15/17 = 8/17 * 17/15 = 8/15
ctg a = 1 : 8/15 = 15/8 = 1 7/8
3) cos a = 0.6
sin a = корень(1-0.36) = корень(0.64) = 0.8
tg a = 0.8 : 0.6 = 8/6 = 1 1/3
ctg a = 1 : 8/6 = 6/8 = 3/4
ответ: x= - 2
Пошаговое объяснение:
2x-16=-5x-30
2x+5x= -30 +16
7x = -14
x= - 2