Odpowiedź:
Zad. 3
a) -3a + 4a - a =
-4a + 4a = 0
b) -3(2b + [tex]\frac{2}{3}[/tex]) + 4 =
-6b - 2 + 4 = -6b + 2
c) 3a + 2b - 4a + b = -a + 3b
d) 5(d + 2) - 3d + 4=
5d + 10 - 3d + 4 = 2d + 14
Zad. 4
a) P= a + a + a + a = a · 4 = 4a
b) P= a + a + a + a = a · 4 = 4a
c) P= b + a + a + a + b = a · 3 + b · 2 = 3a + 2b
d) P= b + a + a + a + b = a · 3 + b · 2 = 3a + 2b
e) P= b + b + b + b + a + a = b · 4 + a · 2 = 2a + 4b
f) P= b + b + b + b + a + a = b · 4 + a · 2 = 2a + 4b
Zad. 5
3x - 2 = 4
3x = 4 + 2
3x = 6 /: 3
x = 2 Odp. D (2)
Zad. 6
a) k + 3 = 12 k = 9
b) d : 5 = 4 d = 20
c) m - 12 = 6 m = 18
d) f · 2 + 2 = 24 f = 11
Zad. 7
a) 2 + x = 7
x = 7 - 2
x = 5
b) x - 5 = 12
x = 12 + 5
x = 17
c) 5x + 4 = 29
5x = 29 - 4
5x = 25 /: 5
x = 5
d) 2 = 3x - 4
-3x = -4 - 2
-3x = -6 /: (-3)
x = 2
e) 2(x + 5) = 16
2x + 10 = 16
2x = 16 - 10
2x = 6 /:2
x = 3
f) [tex]\frac{1}{5}[/tex](x + 10) = 4
[tex]\frac{1}{5}[/tex]x + 2 = 4
[tex]\frac{1}{5}[/tex]x = 4 - 2
[tex]\frac{1}{5}[/tex]x = 2 / · 5
x = 10
Zad. 8
a) 4α + 60° = 180°
4α = 180° - 60°
4α = 120° /: 4
α = 30°
b) 4β - 40° = 180°
4β = 180° + 40°
4β = 220° /: 4
β = 55°
c) 3x + 2 = x + 6
3x - x = 6 - 2
2x = 4 /: 2
x = 2
d) 2 + 4y = 6 + 2y
4y - 2y = 6 - 2
2y = 4 /: 2
y = 2
Zad. 9
O = 24 cm (O = obwód)
O = x · 2 (długość) +[tex]\frac{1}{2}[/tex] · 2(szerokość)
O = 2x + x
O = 3x
3x = 24cm / : 3
x = 8 cm
szerokość = [tex]\frac{1}{2} x[/tex] = [tex]\frac{1}{2}[/tex] · 8
szerokość = 4cm
długość (dł) = x
dł = 8cm
O = x · 2 + [tex]\frac{1}{2} x[/tex] · 2
