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Use Subsitution to Solve a Pair of Linear Equations

Example: Solve the following system of equations using substitution

f(n) = $\begin{cases} y = 2x\\ 3x+y= 10\end{cases}$

To solve this, we substitute equation 1 for y in equation 2

$3x + y = 10$

$3x + (2x) = 10$

$5x / 5 = 10 /5$

$x = 2$

Now that we know the value of x, we can plug it back into equation 1 to find the value of y.

$y = 2x$

$y = 2*(2)$

$y = 4$

So our final answer is x = 2 and y = 4