Odpowiedź:
S = [tex]\frac{a+2t}{3}[/tex]/*3
3S = a + 2t
3S - a = 2t/:2
[tex]t=\frac{3S-a}{2}[/tex]
P = t - 3rt + 2
P - t - 2 = -3rt /: (-3t)
[tex]r = \frac{P - t -2}{-3t}[/tex]
[tex]r = \frac{t +2-P}{3t}[/tex]
[tex]F=\frac{4y-z}{3}[/tex]/*3
3F = 4y - z
3F - 4y = - z/:-1
z = 4y - 3F
