( X + 3 ) / 4 - ( y + 2 ) / 2 = 0
X + 3 - 2( y + 2 ) = 0
X + 3 - 2y - 4 = 0
X = 2y + 1
3x + y = 1
3( 2y + 1 ) + y = 1
6y + 3 + y = 1
7y = - 2
y = - 2/7
X = 2•( - 2/7 ) + 1 = - 4/7 + 7/7 = 3/7
Ответ ( 3/7 ; - 2/7 )
метод интервалов:
1. x²-11x+28=0.
a=1, b=-11, c=28
D=(-11)²-4*1*28=121-112=9
x₁=4, x₂=7
2. +++++(4)-----(7)+++++++>x
3.
x∈(-∞;4)∪(7;∞)