Solve the system by the best method. Use set notation to express the solution set.
-$$\left\{ \begin{array} { l }
x + y = 6 \
y = 2 x
\end{array} \right.$$
A) $\{ ( 2 , - 4 ) \}$
B) $\{ ( - 2 , - 4 ) \}$
C) $\{ ( - 2,4 ) \}$
D) $\{ ( 2,4 ) \}$

Question

Solve the system by the best method. Use set notation to express the solution set.
-$$\left\{ \begin{array} { l } 
x + y = 6 \
y = 2 x
\end{array} \right.$$
A) $\{ ( 2 , - 4 ) \}$
B) $\{ ( - 2 , - 4 ) \}$
C) $\{ ( - 2,4 ) \}$
D) $\{ ( 2,4 ) \}$

Quizplus · Accepted Answer

Substituting $y = 2x$ into the first equation gives $x + 2x = 6$, which simplifies to $3x = 6$. Solving for $x$ gives $x = 2$. Substituting $x = 2$ into $y = 2x$ gives $y = 4$. Therefore, the solution is $(2, 4)$.

Solve the System by the Best Method {x+y=6y=2x\left\{ \begin{array} { l } x + y = 6 \\y = 2 x\end{array} \right.{x+y=6y=2x​

Solve the System by the Best Method $\left\{ \begin{array} { l } x + y = 6 \\y = 2 x\end{array} \right.$