NÅGRA KOMMENTARARER TILL LÖSNINGARNA

2640a
A= 3b
3b=
A
3b
A
=
3 3
A
b =
3
( byt led )
( div 3)
2642a
U
I =
R
U
R⋅ I = R ⋅
R
R⋅ I = U div I
R= U / I
( mult R)
( )
2650a
3x+ 5= 26
3x= 26−5 3x= 21
21
x = = 7
3
2652b
2( x + 1) = 26
2x+ 2= 26
2x= 26−2 2x= 24
24
x = = 12
2
LÖSNINGAR DEL B
2640c
pV = c
pV
c
=
p p
c
V =
p
2642c
( div p)
0,87
( mult n)
d =
n
0,87
nd ⋅ = n⋅
n
nd = 0,87 ( div d )
n= 0,87 / d
2650c
17 = 5 + 4x
− 4x= 5−17 − 4x=−12 −12
x = = 3
−4
2652d
800 = 200(3s + 1)
800 = 600s + 200
− 600s = 200 −800
− 600s =−600
−600
s = = 1
−600
2641b
p
Z =
b
p
b⋅ Z = b ⋅
b
bZ = p
p= bZ
( mult b)
( byt led )
2646a
2
U
p =
R
2
U
R⋅ p= R ⋅
R
2
Rp= U div p
2
R= U / p
( mult R)
( )
2651a
5(4x + 1) = 45
20x + 5 = 45
20x = 45 − 5
20x = 40
40
x = = 2
20
2653c
3 2 4
x ⋅10 − 10 = 10
1000x− 100 = 10000
1000x = 10000 + 100
1000x = 10100
10100
x = = 10,1
1000
2641d
RT
p =
V
RT
V ⋅ p = V ⋅
V
pV = RT
RT = pV
RT
pV
=
R R
T = pV / R
( mult V )
( byt led )
( div R)
2646b
2
R = U / p
2
R = 220 / 75
R = 645 ohm
2651c
144 = 12(5 −14
k)
144 = 60 −168k
168k = 60 −144
168k =−84
−84
x = =−12
168
46
2653d
−4 −3 −2
10 = 10 + y ⋅10
0,0001 = 0,001+ 0,01y
− 0,01y = 0,001−0,0001 − 0,01y = 0,0009
0,0009
y = =−0,09
−0,01