Solve the system by the addition method. If there is no solution or an infinite number of solutions, so state. Use set
notation to express the solution set.
-$$\left\{ \begin{array} { l }
7 x - 2 y = 6 \
- 21 x + 6 y = - 24
\end{array} \right.$$
A) $\{ ( 7,6 ) \}$
B) $\{ ( 3,4 ) \}$
C) no solution; $\varnothing$
D) $\left\{ \left( \frac { 7 } { 9 } , - \frac { 2 } { 9 } \right) \right\}$

Question

Solve the system by the addition method. If there is no solution or an infinite number of solutions, so state. Use set
notation to express the solution set.
-$$\left\{ \begin{array} { l } 
7 x - 2 y = 6 \
- 21 x + 6 y = - 24
\end{array} \right.$$
A) $\{ ( 7,6 ) \}$
B) $\{ ( 3,4 ) \}$
C) no solution; $\varnothing$
D) $\left\{ \left( \frac { 7 } { 9 } , - \frac { 2 } { 9 } \right) \right\}$

Quizplus · Accepted Answer

Multiplying the first equation by 3 gives $21x - 6y = 18$, which contradicts the second equation $-21x + 6y = -24$, indicating parallel lines and thus no solution.

Solve the System by the Addition Method {7x−2y=6−21x+6y=−24\left\{ \begin{array} { l } 7 x - 2 y = 6 \\- 21 x + 6 y = - 24\end{array} \right.{7x−2y=6−21x+6y=−24​

Solve the System by the Addition Method $\left\{ \begin{array} { l } 7 x - 2 y = 6 \\- 21 x + 6 y = - 24\end{array} \right.$