Question

Są dwie kartki zadań prosiłabym o pomoc , bo to hehe na zaliczenie klasówki.

Answer 1

Zad.11
s = 495m = 0,495 km
t = 1,5s = 0,025h

s = 3,3 km
x - poszukiwany czas

0,025h = 0,495 km
x = 3,3 km

x = (3,3 * 0,025) : 0,495
x = 0,0825 : 0,495
x = 0,1(6) h
x w przybilżeniu = 0,17 h
x = 10,2 s

Zad.20
a)
2(x -y) + 3(x - 5) = 4
3(x + 2) - (y -3) = 5

2x - 2y + 3x - 15 = 4
3x + 6 - y + 3 = 5

5x - 2y = 19
- y = -3x -4/: (-1)

5x - 2(3x + 4) = 19
y = 3x + 4

5x - 6x - 8 = 19
y = 3x + 4

-x = 11/: (-1)
y = 3x + 4

x = -11
y = -29

b)
y + 2x = 11
2x - 6y = 4

y = 11 - 2x
2x -6(11 - 2x) = 4

y = 11 - 2x
2x - 66 + 12x = 4

y = 11 - 2x
14x = 70/: 14

y = 11 - 2x
x = 5

y = 1
x= 5

c)
x - y + 2 = 0
2 i 1/2 y - 1 i 1/2 x = 2

x = y - 2
5/2y - 3/2x = 2

x = y - 2
5/2y - 3/2( y - 2) = 2


x = y - 2
y= - 1

x = -3
y = -1

d)
y + 9/3 + 2 - x/4 = 1 - 2x
2y - 3x/4 = 2/3y + 1

4y + 36/12 + 6 - 3x/12 = 1-2x
6y - 9x/12 - 8/12y = 1

(4y + 42 - 3x)/12 = 1-2x
(16/3y - 9x)/12 = 1

1/3y + 3,5 - 1/4x = 1 - 2x
2/3y - 0,75x = 1

1/3y + 7/4x = -2,5
2/3y - 0,75x = 1

1/3y = -2,5 - 7/4x /: 1/3
2/3y - 0,75x = 1

y = -7,5 - 5,25x
2/3( -7,5 - 5,25x) - 0,75x = 1

y = -7,5 - 5,25x
- 4,25x = 6/: (-4,25)

y = -7,5 - 5,25x
x = -1,41

y = -14,90
x = -1,41

e)
2(x -3) - y = 4
3(y + 2) + 2x = 0

2x - 6 - y = 4
3y + 6 + 2x = 0

-y = 10 - 2x/: (-1)
3y + 6 + 2x = 0

y = -10 + 2x
-30 - 6x + 2x = 0

y = -10 + 2x
-4x = 30/: (-4)

y = -10 + 2x
x = -7,5

y = -25
x = - 7,5

f)
x/2 + y = 4
x - y/3 = 1

1/2x + y = 4
x - 1/3y = 1

1/2x + y = 4
x = 1 + 1/3y

1/2 + 7/6y = 4
x = 1 + 1/3y

7/6y = 4 - 1/2
x = 1 + 1/3y

7/6y = 7/2/ : 7/6
x = 1 + 1/3y

y = 3
x = 2


Ad.1
3x - 8 + x = 2(2x - 4)
4x - 8 = 4x - 8

Odp. C

Ad.3
Odp.A

Ad.4
Odp.C

Ad.8
-3x + 4y = 14
2x - 3y = -10

-3x + 4y = 14
2x = 3y - 10/: 2

-3x + 4y = 14
x = 3/2y - 5

- 4,5 + 15 -14 = -4y
x = 3/2y - 5

-4y = -3,5/: (-4)
x = 3/2y - 5

y = 0,875
x = -3,6875