1)8/7-23/49=56/49-23/49=33/49
2)(33/49)/(22/147)=33/49*147/22=3/1*3/2=9/2
3)6/10*4/15=12/225
4)12/225*5/2=6/45
5)9/2-6/45=(405-12)/90=393/90=131/30
6)3,75 : 1 1/2=15/4*2/3=5/2
7)131/30+5/2=(131+225)/30=356/30=178/15
8)178/15:2.2=178/15*5/11=178/3*1/11=178/33
А^2 - в^2=(а+в)(а-в) значит
23,04-z^2=(4,8+z)(4,8-z)
значи правильный ответ (4,8-z)
Решение
<span>2 ㏒²₂ x - 5 ㏒₂x+2=0
ОДЗ: x > 0
log</span>₂ = t
2t² - 5t + 2 = 0
D = 25 - 4*2*2 = 9
t₁ = (5 - 3)/4
t₁ = 1/2
t₂ = (5 <span>+ 3)/4
t</span>₂ = 2
1) log₂ x = 1/2
x₁ = 2¹/²
x₁ = √2
<span>2) log₂ x = 2</span>
x₂ = 2²
x₂ = 4
3ху*(4уz) = 12xy²z
(3b⁴c)²=9b⁸c²
(x+2)(x+5)=x²+5x+2x+10=x²+7x+10
(5a² -8ab +2a) :2 = 2,5а²-4ab+a
3y²+5y+7 -2y²-3y -5 = (3y² -2y²) + (5y-3y) + (7-5) = y² +2y +2