Odpowiedzi

2010-02-04T21:28:40+01:00
X=cyfra dziesiatek
y=cyfra jedności

x+y=9
(10x+y)×(10y+x)=1944
x=9-y
100xy+10x²+10y²+xy=1944

100y(9-y)+10(9-y)²+10y²+y(9-y)=1944
900y-100y²+10(81-18y+y²)+10y²+9y-y²=1944

900y-100y²+810-180y+10y²+10y²+9y-y²=1944
-81y²+729y-1134=0
Δ=b²-4ac=531441-367416=164025
√Δ=405

y₁=(-b-√Δ):2a=(-729-405):-162=+7
y₂=(-729+405):-162=+2
odp. ta liczba to 72 lub 27
1 3 1
2010-02-04T21:32:44+01:00
X=cyfra dziesiatek
y=cyfra jedności

x+y=9
(10x+y)×(10y+x)=1944

x=9-y
100xy+10x²+10y²+xy=1944

100y(9-y)+10(9-y)²+10y²+y(9-y)=1944
900y-100y²+10(81-18y+y²)+10y²+9y-y²=1944

900y-100y²+810-180y+10y²+10y²+9y-y²=1944
-81y²+729y-1134=0
Δ=b²-4ac=531441-367416=164025
√Δ=405

y₁=(-b-√Δ):2a=(-729-405):-162=+7
y₂=(-729+405):-162=+2

Opr. 27 lub 72
1 4 1