Odpowiedź:
9.
a)
2P = ef /e
2P/e = f
b)
H = V/(1/3ab)
H= 3abV
c)
2P = (a+b)*h /h
2P/h = a+b
b= 2P/h - a
d)
d/√2 = a
e)
2h = a√3
2h/√3= a
f)
2P = r(a+b+c) /r
2P/r = a+b+c
a = 2P/r -b-c
10.
a)
ab = 48
2bc = 36
5c = 15/5
c = 3
2b*3 = 36 /3
2b = 12 /2
b = 6
6a=48/6
a = 8
b)
3a +b = - 10
5b - 2c = 3
2/7c = 1 /2/7
c = 3,5
5b - 2* 3,5 = 3
5b - 7 = 3
5b = 10/5
b = 2
3a + 2 = - 10
3a = -12 /3
a = -2
11.
a)
(2x + 4) * 5 = 20 /5
2x + 4 = 10
2x = 10-4 = 6 /2
x = 3
b)
2x + 6x - 4 + 2x + 2 = 18
10x - 2 = 18
10x = 18+2 = 20 /10
x = 2
c)
6x + 6 + 10x/2 = 28 /*2
12x + 12 + 10x = 56
22x = 56 - 12 = 44 /22
x = 2
12.
a)
x + 1 + x +1 + x = 11
3x +2 = 11
3x = 11-2 = 9/3
x = 3
Ramię = x + 1 = 3+1 = 4 cm
Podstawa = x = 3 cm
b)
(x + x + 8) *6 = 12x + 16
(12x + 16)/2 = 30
6x + 8 = 30
6x = 30 - 8 = 24 /6
x = 4
Krótsza podstawa tego trapezu ma więc długość 4 cm.
