Question

Va rog, Puteti sa ma ajutati , va dau Coroana

Answer 1

Răspuns:

1. a) $\frac{b}{a} = \frac{36}{45} = \frac{3*12}{3*15}$= $\frac{3*4}{3*5} = \frac{4}{5}$

b) a= $\frac{5b}{3}$

c) 2x=8*7   x= 56:2= 28  x=28

2.a)  $\frac{a}{3} =5$=> a= 3*5= 15   a=15

$\frac{b}{4} =5$  => b= 4*5=20   b=20

a+b= 15+20=35     a+b=35

b) 6x= 15*7    x= 3*5*7: 2*3= 35:2= 17.5   x= 17.5

c) 200*60:100=120

200+120 = 320 dupa scumpire

3. a) $\frac{x}{2} = \frac{z}{4}$   => x= 2*6:4= 12:4= 3   x=3

$\frac{y}{3} =\frac{z}{4}$=>  y= 3*6:4= 18:4 =4.5

x+y= 3+4.5= 7.5

b) a*3=b*4   a+b=14    a= b*4:3

$\frac{4b}{3}$+b= 14    4b+3b= 14*3   7b= 14*3   b= 14*3:7  =2*3=6

b=6   a= 6*4:3=24:3= 8    a=8

c) $\frac{40x}{100} =6$    x= 6*100:40= 600:40=15   x= 15

4. $\frac{x}{4} = \frac{y}{5} =\frac{z}{7}$   x+y+z= 64  

x= $\frac{4y}{5}$     z= $\frac{7y}{5}$       $\frac{4y}{5} + y+ \frac{7y}{5}$=64   aducem la acelasi numitor

4y+7y+5y= 64*5      16y= 64*5    y= 64*5:16 = 4*5=20  y=20

x= 4*20:5= 4*4=16     x=16

z= 7*20:5= 7*4=28     z=28

5. $\frac{x}{2} =\frac{y}{6}$      2y=6x  y=3x

$\frac{4x+6y}{x+y}$= $\frac{4x+6*3x}{x+3x}$= $\frac{4x+18x}{4x}$= $\frac{22x}{4x}$ = $\frac{11}{2}$

7.

4*(4x-2y)= 1*(2x-y)    

16x-8y= 2x-y   16x-2x= 8y-y   14x=7y  /:7  

y=2x   $\frac{x}{y}$= 2