Graph each system of equations and describe it as consistent and independent, consistent and dependent, or inconsistent.

$\begin{array}{c}27.x+y=4\\ -4x+y=9\end{array}$

Equation of line in slope intercept form is expressed below.

$y=mx+c$

Where m is the slope and c is the intercept of y-axis.

Consider the first equation $x+y=4$.

Subtract both sides by x.

$\begin{array}{c}x+y-x=4-x\\ y=4-x\\ y=-x+4\end{array}$

Now, the equation is in the form $y=mx+c$. Here slope m of the line is $-1$ and intercept of y-axis c is 4.

Now, consider the second equation $-4x+y=9$.

Add the term $4x$on both the sides.

$\begin{array}{c}-4x+y+4x=9+4x\\ y=9+4x\\ y=9x+4\end{array}$

Now, the equation is in the form $y=mx+c$. Here slope m of the line is $9$ and intercept of y-axis is 4.

A system of equations is said to be consistent if there exist a solution to the system.

When two lines intersect each other at one point then there is only one solution to system of equations then the system is said to be consistent and independent.

When two lines are equivalent and their graph overlap each other then there are infinite solutions to system of equations then the system is said to be consistent and dependent.

A system of equations is said to be inconsistent if there no solution to the system that is two lines are parallel to each other.

The red line denotes the equation $x+y=4$ and blue line denotes the equation $-4x+y=9$.

The lines intersect each other at the point $\left(-1,5\right)$. There is a single point such that it satisfy the system of equations. There is an independent solution to system of equations.

Hence, the system of equations is consistent and independent.