How do you write and equation of a line given (10, –2) with a slope of –1?

2 Answers
Oct 24, 2017

y=-x+8y=x+8 or graph{y=-x+8 [-22.8, 22.83, -11.4, 11.4]}

Explanation:

The equation of a line is y=mx+by=mx+b.

Since we know that m=-1m=1 (mm is the slope), the equation will be y=(-1)x+by=(1)x+b

Put in (10, -2) as x=10x=10 and y=-2y=2:

-2=(-1)*10+b->2=(1)10+b
-2=-10+b->2=10+b (Multiply -11 and 1010)
8=b8=b (Add 1010 to both sides)
Flip equation: b=8b=8 (Switch sides)

Whole equation: y=-x+8y=x+8

-xx because -1*x=-x1x=x

Ans: y=-x+8y=x+8

Hopefully I'm right ;/

Oct 24, 2017

y=-x+8y=x+8

Explanation:

"the equation of a line in "color(blue)"slope-intercept form"the equation of a line in slope-intercept form is.

color(red)(bar(ul(|color(white)(2/2)color(black)(y=mx+b)color(white)(2/2)|)))

"where m is the slope and b the y-intercept"

rArry=-x+blarr" is the partial equation"

"to find b substitute "(10,-2)" into the partial equation"

-2=-10+brArrb=8

rArry=-x+8larrcolor(red)" in slope-intercept form"
graph{-x+8 [-10, 10, -5, 5]}