Questions: What is the value of y in the solutions of the system of equations: 3x+4y= 3 and 2x-4y=12? (Suggest using the Addition Method)
Transcript text: What is the value of $y$ in the solutions of the system of equations: $3 x+4 y=$ 3 and $2 x-4 y=12$ ? (Suggest using the Addition Method)
Solution
Solution Steps
Step 1: Write Down the System of Equations
We are given the following system of equations:
\(3x + 4y = 3\)
\(2x - 4y = 12\)
Step 2: Add the Equations to Eliminate \(y\)
To eliminate \(y\), we can add the two equations together. Notice that the coefficients of \(y\) in the two equations are \(+4\) and \(-4\), which will cancel each other out when added.
\[
(3x + 4y) + (2x - 4y) = 3 + 12
\]
Simplifying the left side, we get:
\[
3x + 2x + 4y - 4y = 15
\]
This simplifies to:
\[
5x = 15
\]
Step 3: Solve for \(x\)
Divide both sides of the equation by 5 to solve for \(x\):
\[
x = \frac{15}{5} = 3
\]
Step 4: Substitute \(x\) Back into One of the Original Equations
Now that we have \(x = 3\), substitute this value back into one of the original equations to solve for \(y\). Let's use the first equation:
\[
3x + 4y = 3
\]
Substitute \(x = 3\):
\[
3(3) + 4y = 3
\]
Simplify:
\[
9 + 4y = 3
\]
Step 5: Solve for \(y\)
Subtract 9 from both sides:
\[
4y = 3 - 9
\]
\[
4y = -6
\]
Divide both sides by 4:
\[
y = \frac{-6}{4} = -\frac{3}{2}
\]
Final Answer
The value of \(y\) in the solution of the system of equations is: