Solve the problem.
-$$\left\{ \begin{array} { l }
x + y = - 4 \
y = 3 x
\end{array} \right.$$
A) $\{ ( 1,3 ) \}$
B) $\{ ( - 1,3 ) \}$
C) $\{ ( - 1 , - 3 ) \}$
D) $\{ ( 1 , - 3 ) \}$

Question

Solve the problem.
-$$\left\{ \begin{array} { l } 
x + y = - 4 \
y = 3 x
\end{array} \right.$$
A) $\{ ( 1,3 ) \}$
B) $\{ ( - 1,3 ) \}$
C) $\{ ( - 1 , - 3 ) \}$
D) $\{ ( 1 , - 3 ) \}$

Quizplus · Accepted Answer

Substituting $y = 3x$ into the first equation gives $x + 3x = -4$, which simplifies to $4x = -4$. Solving for $x$ gives $x = -1$. Substituting $x = -1$ back into $y = 3x$ gives $y = 3(-1) = -3$. Therefore, the solution is $(-1, -3)$.

Solve the Problem {x+y=−4y=3x\left\{ \begin{array} { l } x + y = - 4 \\y = 3 x\end{array} \right.{x+y=−4y=3x​

Solve the Problem $\left\{ \begin{array} { l } x + y = - 4 \\y = 3 x\end{array} \right.$