# Question #672cd

Feb 24, 2017

$y = - x + 4 \mathmr{and} y = \frac{1}{4} x + 14$

#### Explanation:

Slope-intercept form of the equation of a straight line is $y = m x + c$

$- 1.1 x - 5.5 y = - 4.4 \text{ } \leftarrow$ re-arrange the equation

$\textcolor{w h i t e}{\ldots \ldots . .} - 5.5 y = 1.1 x - 4.4 \text{ } \leftarrow$ divide by $- 1.1$

$\textcolor{w h i t e}{\ldots \ldots \ldots \ldots \ldots \ldots} y = - x + 4$

Do the same for the other equation:

$0.8 x - 3.2 y = - 11.2 \text{ } \leftarrow$ re-arrange the equation

$\textcolor{w h i t e}{\ldots . .} - 3.2 y = - 0.8 x - 11.2 \text{ } \leftarrow$ divide by $- 3.2$

$\textcolor{w h i t e}{\ldots \ldots \ldots \ldots \ldots .} y = 0.25 x + 14$

$\textcolor{w h i t e}{\ldots \ldots \ldots \ldots \ldots .} y = \frac{1}{4} x + 14$

Now plot the graphs.

The break-even point can be found from the point of intersection of the the two lines.
graph{(-x-y+4)(x/4-y+14)=0 [-21.75, 18.25, -2.72, 17.28]}