Question

Doar cele încercuite ! dau 20 puncte și coroana!

Answer 1

b) (3*32:12+1)/x=6/5
(96:12+1)/x=6/5
(8+1)/x=6/5
9/x=6/5
x=(9*5)/6
x=45/6
x=7,5

c)3/7=x/(2*125:10-4)
3/7=x/(250:10-4)
3/7=x/(25-4)
3/7=x/21
x=(3*21)/7
x=9

d)(7*64:28-1)/x=5/2
(448:28-1)/x=5/2
(16-1)/x=5/2
15/x=5/2
x=30/5
x=6

e)7/5=x/(9*32:12+1)
7/5=x/(288:12+1)
7/5=x/(24+1)
7/5=x/25
x=(7*25)/5
x=7*5
x=35

f)(8*125:20-1)/x=7/6
(1000:20-1)/x=7/6
(50-1)/x=7/6
49/x=7/6
x=(49*6)/7
x=7*6
x=42


a)x/2,8=1,05/0,7
x=(2,8*1,05)/0,7
x=2,94/0,7
x=4,2

c)0,42/1,5=x/35
x=(0,42*35)/1,5
x=14,7/1,5
x=9,8

d)2,8/0,84=16/x
x=(16*0,84)/2,8
x=13,44/2,8
x=4,8

Answer 2

$5.b)\frac{3\cdot2^{5}:12+1}{x}= \frac{6}{5} \\ \\ \frac{3\cdot2^{5}:3\cdot 2^{2} +1}{x}= \frac{6}{5} \\ \\ \frac{(3\cdot2^{5}:3\cdot 2^{2} )+1}{x}= \frac{6}{5} \\ \\ \frac{2^{3}+1}{x}= \frac{6}{5} \\ \\ \frac{9}{x}= \frac{6}{5} \\ \\ 6x=9\cdot5 \\ \\ x= \frac{45}{6}$

$c)\frac{3}{7}= \frac{x}{2\cdot 5^{3} :10-4} \\ \\ \frac{3}{7}= \frac{x}{(2\cdot 5^{3} :2\cdot5)-4} \\ \\ \frac{3}{7}= \frac{x}{ 5^{2}-4 } \\ \\ \frac{3}{7}= \frac{x}{21} \\ \\ 7\cdot x=21 \cdot3 \\ \\ x= \frac{21 \cdot3 }{7} =9 \\ \\ x=9$

$e)\frac{7}{5}= \frac{x}{9\cdot32:12+1} \\ \\ \frac{(7}{5}= \frac{x}{288:12+1} \\ \\ \frac{ 7}{5}= \frac{x}{24+1} \\ \\ \frac{7}{5}= \frac{x}{25} \\ \\ x= \frac{7\cdot25}{5} =35 \\ \\ x=35$

$f) \frac{8\cdot125:20-1}{x} = \frac{7}{6} \\ \\ 7x=6[\cdot(2\cdot4\cdot5\cdot25):20-1] \\ \\ 7x=6(50-1) \\ \\ 7x=6\cdot49 \\ \\ x=42$

$6.a)\frac{x}{2,8} = \frac{1,05}{0,7} \\ \\ x= \frac{2,8 \cdot1,05}{0,7} =4,2 \\ \\ c)\frac{0,42}{1,5} = \frac{x}{35} \\ \\ x= \frac{0,42 \cdot 35}{1,5} =9,8 \\ \\d)\frac{2,8}{0,84} = \frac{16}{x} \\ \\ x= \frac{0,84 \cdot 16}{2,8} =4,8$