Odpowiedź:
Szczegółowe wyjaśnienie:
1.
a) 3 + x = 2x - 5
x - 2x = -5 -3
-x = -8 /*(-1)
x = 8
L = 3 + x = 3+8 = 11
P = 2x - 5 = 16 - 5 = 11
L = P
b) 5(t+6) - 2 = 8t
5t + 30 - 2 = 8t
5t - 8t = -28
-3t = -28
t = 28/3
L = 5(28/3 + 6) -2 = 140/3 + 30- 2 = 46 2/3 + 28 = 74 2/3
P = 8 * 28/3 = 224/3 = 74 2/3
2.
10 + 2x = 16
2x = 6 /:2
x = 3
odp B.
3.
5x - 4 + 4 = 31 + 4
5x = 35
odp C.
4.
a) 5x - 3 = 17
5x = 17 + 3
5x = 20 /:5
x = 4
spr
L = 5x - 3 = 5*4 - 3 = 20 -3 = 17
P = 17
L = P
b) 2x - 5 + 4x = 7 + x - 4
6x - x = 3 + 5
5x = 8 /:5
x = 8/5
spr
L = 2x - 5 + 4x = 2*8/5 - 5 + 4*8/5 = 16/5 + 32/5 - 5 = 48/5 - 5 = 9 3/5 - 5 =
= 4 3/5
P = 7 + x -4 = 7 + 8/5 - 4 = 3 + 1 3/5 = 4 3/5
L = P
5.
Ilość wody w 1 beczce = x
Ilość wody w 2 beczce = x - 48
x + x - 48 = 136
2x = 136 + 48
2x = 184 /:2
x = 92
w 1 beczce są 92 litry wody
w 2 beczce jest 92 - 48 = 44 litry wody
6.
x - cena zeszytu
7x - cena piórnika
5 * x + 7x = 50 - 14
12x = 36 /:12
x = 3
zeszyt kosztował 3 zł
piórnik kosztował 7*x = 7 * 3 = 21 zł
