Метод сложения .
-2 ( x - 5y ) = - 2 × 8
2x+ 4y = 30
-2x + 10 y = - 16
2x + 4y = 30
14y = 14
y = 1
x = 13
Метод подстановки
x = 8 + 5y
2 (8 + 5y ) + 4y = 30
16 + 10y + 4y = 30
14y = 14
y = 1
x = 13
1) <span>-2√0,0049+√2,56 =-2*0,07+1,6=1,46
2)</span>√5X-√12=7⇒5X-12=49⇒5X=61⇒x=12,2
(m-n)^2+m(6n-m)=m^2-2mn+n^2+6mn-m^2=4mn+n^2=4*¼*(-1)+(-1)^2=-1+1=0
A1=-25
d=4
a30=a1+29d
Ответ: 91