How do you find the slope and y-intercept of the graph of 2x + 4y=-8?

1 Answer
Jim G.
Sep 4, 2016

slope #=-1/2#
y-intercept = - 2

Explanation:

The equation of a line in #color(blue)"slope-intercept form"# is

#color(red)(|bar(ul(color(white)(a/a)color(black)(y=mx+b)color(white)(a/a)|)))#
where m represents the slope and b, the y-intercept.

The advantage to having the equation in this form is that m and b can be extracted 'easily'.

Rearrange #2x+4y=-8" into this form"#

subtract 2x from both sides of the equation.

#rArrcancel(2x)-cancel(2x)+4y=-8-2xrArr4y=-2x-8#

now divide both sides by 4 to obtain y.

#rArr(cancel(4)^1 y)/cancel(4)^1=(cancel(-2)^-1)/cancel(4)^2 x-cancel(8)^2/cancel(4)^1#

#rArry=-1/2x-2" is equation in y = mx + b form"#

from this #"slope" =-1/2" and y-intercept" =-2#

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