1)23<24<25
2)55<56<57
3)257<258<259
4)4324<4325<4326
5)999998<999999<1000000
6)1299999<1300000<1300001
6 + 6.5 =12.5 скорость приближения пешеходов
150/ 12.5 = 12 часов
8*2=16 кухня. 16:1/5 = 80 м квартира
2.
1) x²-22x-23≤0
f(x)=x²-22x-23 - парабола, ветви вверх
x²-22x-23=0
D=22² - 4*(-23)=484 + 92=576
x₁= <u>22 - 24 </u>= -1
2
x₂ =<u> 22+24 </u>= 23
2
+ - +
------- -1 ----------- 23 -----------
\\\\\\\\\\\\\\
x∈[-1; 23]
2) x²-3x-10>0
f(x)=x²-3x-10 - парабола, ветви вверх
x²-3x-10=0
D=3² - 4*(-10)=9+40=49
x₁= <u>3-7</u> = -2
2
x₂ = <u>3+7 </u>=5
2
+ - +
-------- -2 ----------- 5 --------------
\\\\\\\\\\ \\\\\\\\\\\\\\\
x∈(-∞; -2)U(5; +∞)
3) (6х-3)(х+4)<0
6(x-3/6)(x+4)<0
(x-1/2)(x+4)<0
x=1/2 x=-4
+ - +
--------- -4 --------------- 1/2 ---------------
\\\\\\\\\\\\\\\\\
x∈(-4; 1/2)
3.
у=√(x²-7x+12)
x²-7x+12≥0
f(x)=x²-7x+12 - парабола, ветви вверх
x²-7x+12=0
D=7²-4*12=49-48=1
x₁=<u>7-1 </u>= 3
2
x₂ =<u> 7+1 </u>=4
2
+ - +
---------- 3 ------------- 4 ----------
\\\\\\\\\ \\\\\\\\\\\
x∈(-∞;3] U [4; +∞)