Question

Graph 3x+y=-10 -x+3y=0

Answer 1

The slope-intercept form of an equation of a line:

`y=mx+b`

m - slope

b - y-intercept

We have the equations in the standard form. Convert to the slope-intercept form:

`3x+y=-10` subtract 3x from both sides

`y=-3x-10`

`-x+3y=0` add x to both sides

`3y=x` divide both sides by 3

`y=(1)/(3)x`

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We need only two points to plot a graph of each function.

`y=-3x-10`

for x = 0 and for x = -3:

`y=-3(0)-10=0-10=-10\to(0,\ -10)\\\\y=-3(-3)-10=9-10=-1\to(-3,\ -1)`

`y=(1)/(3)x`

for x = 0 and for x = -3:

`y=(1)/(3)(0)=0\to(0,\ 0)\\\\y=(1)/(3)(-3)=-1\to(-3,\ -1)`

Look at the picture.