Question

Rozwiąż i sprawdz równania :

a) 2x+5=9

b) 8y-6=2y+12

c)3b+8=4b+10

d) 1 1/6 : x=2,25

e) 5x-4=16+4

f) x+2=8-3x

Oblicz

a) 1 4/5* 2 3/8

b) 8 2/7 : 4/5

Answer 1

a) 2x+5=9

2x=9-5 = 4  /:2

x=2

 

2*2+5=9

 

b) 8y-6=2y+12

6y=18 /:6

y = 3

 

24-6 = 6+12

18=18

 

c)3b+8=4b+10

-b=2  /:(-1)

b=-2

 

-6+8=-8+10

2=2

 

d) 1 1/6 : x=2,25

7/6*1/x = 2,25   /*6x

7 = 13,5x

13,5x=7   / *10/135

x=70/135

 

7/6*135/70=2,25

45/20=2,25

2,25=2,25

 

 

e) 5x-4=16+4

5x=24  /:5

x=4 4/5

 

24/5*5-4=20

24-4=20

20=20

 

f) x+2=8-3x

4x=6   /:4

x=6/4

x=3/2 = 1,5

 

1,5+2=8-3*1,5

3,5=8-4,5

3,5=3,5

 

Zad 2

 

a) 1 4/5* 2 3/8 = 9/5*19/8 = 171/40 = 4 11/40

b) 8 2/7 : 4/5 = 58/7 * 5/4 = 290/28 = 10 10/28 = 10 5/14