Question

Dau coroana celui care da un răspuns corect!!

Answer 1

Explicație pas cu pas:

a)x+y=14

x/y=3/4=>x=3y/4

( 3y/4)+y=14

(3y+4y)/4=14

7y=14×4

7y=56

y=56/7

y=8

x+8=14

x=14-8

x=6

b)y/x=5/2=>y=5x/2

y-x=9

(5x/2)-x=9

(5x/2)-(2x/2)=9

(5x-2x)/2=9

3x/2=9

3x=9×2

3x=18

x=18/3

x=6

y-6=9

y=6+9

y=15

c)7/x=3/y<=>y/x=3/7

5x-4y=69

y=3x/7

5x-4(3x/7)=69

5x-(12x/7)=69

(35x/7)-(12x/7)=69

(35x-12x)/7=69

23x/7=69

23x=69x7

23x=483

x=483/23

x=21

5×21-4y=69

105-4y=69

4y=105-69

4y=36

y=36/4

y=9

d)1/x=2/y<=>y/x=2=>y=2x

x²+y²=45

x²+(2x)²=45

x²+4x²=45

5x²=45

x²=9

$x = \sqrt{9}$

x=3

y=2x

y=6

MULT SUCCES!!