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1)13х=-26
х=-26:13
х=-2
2)-6х=42
х=42:(-6)
х=-7
3)3х-3=2х+4
3х-2х=4+3
х=7
4)3х-15-2х-8=5х
3х-2х-5х=15+8
-4х=23
х=23:(-4)
х=5,75
1)
(x-1)/(y+2)=6/7
7*(x-1)=6*(y+2)
(7*(x-1))²=(6*(y+2))²
49*(x-1)²=36*(y+2)²
2)
(x-1)²+(y+2)²=85/9 |×36
36*(x-1)²+36*(y+2)²=85*36/9
36*(x-1)²+36*(y+2)²=85*4
36*(x-1)²+49*(x-1)²=85*4
85*(x-1)²=85*4 |÷85
(x-1)²=4
x-1=2 x₁=3 ⇒
(3-1)/(y+2)=6/7
y+2=2*(7/6)=7/3=2¹/₃
y₁=1/3.
x-1=-2 x₂=-1 ⇒
(-1-1)/(y+2)=6/7
y+2=-2*7/6=-14/6=-7/3=-2¹/₃
y₂=-4¹/₃.
Ответ: x₁=3 y₁=1/3 x₂=-1 y₂=-4¹/₃.