5√8 * х=50<span>√8 - 10х
5</span>√4 * √2 * х=50√4 * √<span>2 - 10х
5*2*</span>√2*х=50*2*√2-10х
10*√2*х=100√2-10х
10*√2*х+10х=100√2
(10*√2+10)*х=100√2
х=100√2 / 10√2+10=100√2 / 10*(√2+1)=10√2 / √2+1
У=9-2х
3х-5(9-2х)-20=0.
У=9-2х
3х-45+10х-20=0
У=9-2х
13х=45+20
у=9-2х
13х=65
У=9-2х
Х=5
У=9-2*5
Х=5
У=-1
Х=5
Ответ:(5;-1)
Окееееей:
a) cos (135) = cos(90 + 45) = cos (90) * cos (45) - sin (90) * sin (45) = - sin(45) = - sqrt(2)/2
б) sin (-75) = sin (-30 - 45) = sin (-30) * cos (45) - sin (45) * cos (-30) = -1/2 * sqrt(2)/2 - sqrt(2)/2 * sqrt(3)/2 = -sqrt(2)/4 - sqrt(6)/4 = -1/4 * (sqrt(6) + sqrt(2)
Пуф-пуф.
а) cos (47) * cos (13) - sin (47) * sin (13) = cos (60) = 1/2
б) sin (12.20) * cos (47.40) + cos(12.20) + sin (47.40) = sin (60) = sqrt(3)/2
12x+y=17
y=-12x+17
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