How do you find the slope given #x+9y=18#?

2 Answers
smendyka
Mar 14, 2018

See a solution process below:

Explanation:

This equation is in the Standard Linear Form. The standard form of a linear equation is: #color(red)(A)x + color(blue)(B)y = color(green)(C)#

Where, if at all possible, #color(red)(A)#, #color(blue)(B)#, and #color(green)(C)#are integers, and A is non-negative, and, A, B, and C have no common factors other than 1

#color(red)(1)x + color(blue)(9)y = color(green)(18)#

The slope of an equation in standard form is: #m = -color(red)(A)/color(blue)(B)#

Substituting gives a slope of:

#m = -color(red)(1)/color(blue)(9)#

Jim G.
Mar 14, 2018

#"slope "=-1/9#

Explanation:

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

#•color(white)(x)y=mx+b#

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

#"rearrange "x+9y=18" into this form"#

#"subtract x from both sides"#

#cancel(x)cancel(-x)+9y=-x+18#

#rArr9y=-x+18#

#"divide all terms by 9"#

#(cancel(9) y)/cancel(9)=-1/9x+2#

#rArry=-1/9x+2larrcolor(red)"in slope-intercept form"#

#rArr"slope m"=-1/9#

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