1) x + 7 ≥ 0 ⇒ x ≥ - 7
2) 5 - x > 0 ⇒ - x > - 5 ⇒ x < 5
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Область определения - все значения x ∈ [- 7 ; 5)
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{а-b=8, а-b=8,
{a+b=-6. a+b=-6
{a=2 , a=2
{a+b=-6
{a=2,
{a-b=8
{ a=2 ,
{b=-6, 2-b=8
{a=2 -b=8-2
-b=6÷(-1)
b=-6
4a-b=4×2-(-6)=8+6=14
{2y-15x=3,
{5x-y=-1.
{2y-15x=3,
{-y=-1-5x
{2y-15x=3,
{y=1+5x
{x=-0,2 2×(1+5x)-15x=3
{y=1+5×(-0,2 ) 2+10x-15x=3
{x=-0,2. -5x=1÷(-5)
{y=0 x=-0,2. y-x=0-(-0,2)=0,2
1) 3x(x²-4)=0
3x=0
x=0
x²=4
x=2 x=-2
2) x(x²-1) -5(x²-1)=0
(x²-1)(x-5)=0
x²-1=0
x=1 x=-1
x-5=0
x=5