What is the y-value of the solution to the system of equations?

3x + 5y = 1

7x + 4y = −13

−3
−1
2

1 answer

To solve the system of equations:

  1. 3x + 5y = 1 (Equation 1)
  2. 7x + 4y = -13 (Equation 2)

We can use the method of substitution or elimination. Here, I will use substitution.

First, let's solve Equation 1 for \(y\):

\[ 5y = 1 - 3x \] \[ y = \frac{1 - 3x}{5} \]

Now we substitute this expression for \(y\) into Equation 2:

\[ 7x + 4\left(\frac{1 - 3x}{5}\right) = -13 \]

Multiply through by 5 to eliminate the fraction:

\[ 35x + 4(1 - 3x) = -65 \] \[ 35x + 4 - 12x = -65 \] \[ 23x + 4 = -65 \] \[ 23x = -65 - 4 \] \[ 23x = -69 \] \[ x = -3 \]

Now we'll substitute \(x = -3\) back into the equation we derived for \(y\):

\[ y = \frac{1 - 3(-3)}{5} \] \[ y = \frac{1 + 9}{5} \] \[ y = \frac{10}{5} = 2 \]

Thus, the y-value of the solution to the system of equations is:

\[ \boxed{2} \]