Questions: 6. We want to solve the following system of equations using the substitution method.
Equation 1 y=5x-42
Equation 2 3x+4y=39
6a First solve for x.
6. We want to solve the following system of equations using the substitution method.
Equation 1 y=5x-42
Equation 2 3x+4y=39
6a First solve for x.
Solution
Solution Steps
To solve the system of equations using the substitution method, we first use Equation 1, which already expresses \( y \) in terms of \( x \). We substitute this expression for \( y \) into Equation 2. This substitution will allow us to solve for \( x \).
Step 1: Substitute \( y \) in Equation 2
We start with the two equations:
\( y = 5x - 42 \)
\( 3x + 4y = 39 \)
We substitute \( y \) from Equation 1 into Equation 2:
\[
3x + 4(5x - 42) = 39
\]
Step 2: Simplify the Equation
Now, we simplify the equation:
\[
3x + 20x - 168 = 39
\]
Combining like terms gives:
\[
23x - 168 = 39
\]
Step 3: Solve for \( x \)
Next, we isolate \( x \):
\[
23x = 39 + 168
\]
\[
23x = 207
\]
\[
x = \frac{207}{23} = 9
\]