Wzór ogólny funkcji liniowej:
y = ax + b
[latex] left { {{2 frac{1}{2} = frac{1}{2} a+b} atop {2 frac{1}{2} =-2a+b}}
ight. [/latex]
[latex] left { {{5=a+2b} atop {5=-4a+2b}}
ight. [/latex]
[latex] left { {{a=5-2b} atop {5=-4(5-2b)+2b}}
ight. [/latex]
[latex] left { {{a=5-2b} atop {5=-20+8b+2b}}
ight. [/latex]
[latex] left { {{a=5-2b} atop {25=10b}}
ight. [/latex]
[latex] left { {{a=5-2b} atop {b=2 frac{1}{2} }}
ight. [/latex]
[latex] left { {{a=5-2*2 frac{1}{2} } atop {b=2 frac{1}{2} }}
ight. [/latex]
[latex] left { {{a=5-5} atop {b=2 frac{1}{2} }}
ight. [/latex]
[latex] left { {{a=0} atop {b=2 frac{1}{2} }}
ight. [/latex]
[latex]y=2 frac{1}{2} [/latex]