3x + y = 9 (I)
y = –4x + 10 (II)
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\(\left \{ {{3x + y = 9 } \atop {y = -4x + 10 }} \right.\)
Pass the incognito "4x" to the first term, changing the signal when changing sides.
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simplify by (-1)
\(\left \{ {{3x + y = 9.(-1)} \atop {4x + y = 10 }} \right.\)
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\(\left \{ {{- 3x - \diagup\!\!\!\!y =-9} \atop {4x + \diagup\!\!\!\!y = 10}} \right.\)
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\(\left \{ {{- 3x = - 9} \atop {4x = 10}} \right.\)
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\(\boxed{x = 1}\)
Substitute in equation (I) to find the value of "Y".
3x + y = 9 (I)
3*(1) + y = 9
3 + y = 9
y = 9 - 3
\(\boxed{y = 6}\)
Answer:
\(\boxed{\boxed{ \left \ {{x=1} \atop {y=6}} \right. }}\)
