4x-y=7
x=-2
find y
You asked:
Solve the equations \[\begin{aligned}4 x - y &= 7\\x &= -2\end{aligned}\] for the unknown \(y\).
MathBot Answer:
The system of linear equations has exactly one solution.
\[y = -15\]
Solve \(4 x - y = 7\) for \(x\). \[x = \frac{y}{4} + \frac{7}{4}\]
Substitute \(\frac{y}{4} + \frac{7}{4}\) for \(x\) in \(x = -2\) and simplify. $$\begin{aligned}x &= -2 \\ \left(\frac{y}{4} + \frac{7}{4}\right) &= -2 \\ y &= -15 \end{aligned}$$
Use substitution of the numerical value of \(y\) to get the values of \(x\). $$\begin{aligned}x &= \frac{y}{4} + \frac{7}{4} \\ x &= - \frac{15}{4} + \frac{7}{4} \\ x &= -2\end{aligned}$$