6-4=2 Яся старше на 2года Валентины
<span>31-(10-3)=24
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1) 54×19=1026(км)- ехал первый поезд.
2)49×2 = 98 ( км) ехал второй поезд.
3) 1026+98=1124( км) между Москвой и Архангельском.
Ответ: 1124 км между Москвой и Архангельском.
1)
/////////////////////////////////////////////
--------(1)-------------------(2,5)--------------
\\\\\\\\\\\\\\\\\\\\\\\\\\
x∈(2,5;∞)
2){x≥1,5
{x≤3
//////////////////////////////////////////////////////
---------[1,5]----------------------[3]---------------
\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
x∈[1,5;3]
3
/////////////////////////////////////////////////////
------------(-2)---------------------(-1,5)----------------
\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
x∈(-2;-1,5)
4
{5x<5⇒x<1
{x<12
\\\\\\\\\\\\\\
---------(1)---------------------(12)-----------
///////////////////////////////////////////
x∈(-∞;1)
5
{x≤15
{x≥6
\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
--------[6]------------------[15]-----------
/////////////////////////////////////////
x∈[6;15]
6
{x>0
{x≥-7
/////////////////////////////////////////////
----------[-7]--------------------(0)----------------
\\\\\\\\\\\\\\\\\\
x∈(0;∞)
А) Сначала упростим выражение:
<span>0,7542x+0,2458-20,9=0,7542х-20,6542
Вычисляем:
0,7542*220-20,6542=145,2716
б) 66,6у-44,4у+8,11=22,2у+8,11
22,2*10+8,11=222+8,11=230,11</span>