Question

For homework, Randall is solving the system of linear equations in the box.

Answer 1

The given system of equation is

$\begin{gathered} 3x+4y=25\rightarrow(1) \\ 4x-7y=-16\rightarrow(2) \end{gathered}$

To solve the system we can find y in terms of x and the numerical term

$\begin{gathered} 4y=25-3x \\ y=\frac{25-3x}{4}\rightarrow(3) \end{gathered}$

Now, we can substitute y in equation (2) by equation (3)

$4x-7(\frac{25-3x}{4})=-16$

Then the correct answer is A (first choice)