Solve the system of equations.
-$$\begin{aligned}
x _ { 1 } + 3 x _ { 2 } + 2 x _ { 3 } & = 11 \
4 x _ { 2 } + 9 x _ { 3 } & = - 12 \
x _ { 3 } & = - 4
\end{aligned}$$
A) $( 1 , - 4,6 )$
B) $( - 4,6,1 )$
C) $( 1,6 , - 4 )$
D) $( - 4,1,6 )$

Question

Quizplus · Accepted Answer

Given $x_3 = -4$, substituting this into the second equation gives $4x_2 + 9(-4) = -12$, which simplifies to $4x_2 - 36 = -12$, leading to $4x_2 = 24$, so $x_2 = 6$. Substituting $x_2 = 6$ and $x_3 = -4$ into the first equation gives $x_1 + 3(6) + 2(-4) = 11$, which simplifies to $x_1 + 18 - 8 = 11$, leading to $x_1 = 1$. Therefore, the solution is $(1, 6, -4)$.

Solve the System of Equations x1+3x2+2x3=114x2+9x3=−12x3=−4\begin{aligned}x _ { 1 } + 3 x _ { 2 } + 2 x _ { 3 } & = 11 \\4 x _ { 2 } + 9 x _ { 3 } & = - 12 \\x _ { 3 } & = - 4\end{aligned}x1​+3x2​+2x3​4x2​+9x3​x3​​=11=−12=−4​

Solve the System of Equations $\begin{aligned}x _ { 1 } + 3 x _ { 2 } + 2 x _ { 3 } & = 11 \\4 x _ { 2 } + 9 x _ { 3 } & = - 12 \\x _ { 3 } & = - 4\end{aligned}$