[tex]f(x)=(4-5m)x+3\\
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M=(\frac{1}{2} ,6),~~M\in f(x)\\
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(4-5m)\cdot \frac{1}{2} +3=6~~\mid \cdot 2\\
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4-5m+6=12\\
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-5m+10=12\\
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-5m=12-10\\
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-5m=2~~\mid \div (-5)\\
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m=-\dfrac{2}{5} \\
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f(x)=(4-5\cdot (-\frac{2}{5}) )x+3\\
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f(x)=(4+2)x+3\\
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f(x)=6x+3\\
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Sprawdzam:\\
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f(\frac{1}{2} )=6\cdot \frac{1}{2} +3\\
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f(\frac{1}{2} )=3+3\\
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f(\frac{1}{2} )=6~~\Rightarrow ~~gdy ~~m=-\dfrac{2}{5} ~~to~~M\in f(x)[/tex]
