Răspuns:
x + 3y = 14
2y + z = 14
a) x + 5y + z = ??
[tex] \bf x + 3y = 14[/tex]
[tex] \underline{ \bf 2y + z = 14 \: \: \: \: \: \: \:\:}( + ) [/tex]
[tex] \bf x + 3y + 2y + z = 14 + 14[/tex]
[tex] \pink{ \boxed{\bf x + 5y + z = 28}}[/tex]
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b) 3x + 15y + 3z = ??
[tex]\bf x + 3y = 14 \: \: \: \bigg| \cdot3 \implies3x + 9y = 42 [/tex]
[tex] \bf 2y + z = 14 \:\:\bigg| \cdot3 \implies \underline{ 6y + 5z = 42 \: \: \: \: \:\:\:}( + ) [/tex]
[tex] \purple{ \boxed{ \bf 3x + 15y + 3z =84}}[/tex]
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c) 5x + 11y - 2z = ??
[tex]\bf x + 3y = 14 \: \: \: \bigg| \cdot5 \implies5x + 15y = 70[/tex]
[tex] \bf 2y + z = 14 \:\:\bigg| \cdot2 \implies \underline{ 4y + 2z = 28 \:\:\:\:\:\:\:}(-) [/tex]
[tex] \bf 5x + 15y - 4y - 2z= 70 - 28[/tex]
[tex] \blue{ \boxed{\bf 5x + 11y - 2z= 42}}[/tex]
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d) 5x + 19y + 2z = ??
[tex]\bf x + 3y = 14 \:\:\: \bigg|\cdot5 \implies5x + 15y = 70[/tex]
[tex]\bf 2y + z = 14 \:\:\bigg| \cdot2 \implies \underline{ 4y + 2z = 28 \:\:\:\:\:\:\:}( + )[/tex]
[tex] \bf 5x + 15y + 4y + 2z= 70 + 28[/tex]
[tex] \red{ \boxed{\bf 5x + 19y+ 2z= 98}}[/tex]
[tex] = = pav38 = = [/tex]
