Question

4x+5y=7 Y=3x+9What is x? What is y?

Answer 1

As given by the question

There are given that the system of the equation:

$\begin{gathered} 4x+5y=7\ldots(1) \\ y=3x+9\ldots(2) \end{gathered}$

Now,

Put the value of equation (2) into equation (1) instead of y:

So,

From the equation (1):

$\begin{gathered} 4x+5y=7 \\ 4x+5(3x+9)=7 \\ 4x+15x+45=7 \end{gathered}$

Then,

$\begin{gathered} 4x+15x+45=7 \\ 19x+45=7 \\ 19x=7-45 \\ 19x=-38 \\ x=-\frac{38}{19} \\ x=-2 \end{gathered}$

Then,

Put the value of x into equation (2) to find the y:

So,

$\begin{gathered} y=3x+9 \\ y=3(-2)+9 \\ y=-6+9 \\ y=3 \end{gathered}$

Hence, the value of x and y is shown below:

$\begin{gathered} x=-2 \\ y=3 \end{gathered}$