Linear Equations in Two Variables

Question

Directions:

Use the intercept form to find the equation of the line with the given intercepts. The intercept form of the equation of a line with intercepts (a,0) and (0,b) is

(x/a)+(y+b)=1, a=/=0, b=/=0

 

Problems:

68) x-intercept: (2,0)

y-intercept: (0,3)

 

72) point on line: (1,2)

x-intercept: (c,0)

y-intercept: (o,c), c=/=0

 

To find the answers, I followed this: http://answers.yahoo.com/question/index?qid=20090913090505AABfe1X

However, I don\'t understand exactly what the directions are asking or what the use of the given information is??

Answer 1

 

68) x-intercept: (2,0)

y-intercept: (0,3)

Slope-intercept form line equation is y = mx + b, where m is lope and b is y-intercept.

Substitute b = 3 in the equation, y = mx + 3

find the slope m by substituting any point on the line (2, 0)

0 = m * 2 + 3

subtract 3 form each side

-3 = 2m

divide each side by 2

m = -3/2

The line equation is y = -3/2x + 3

Answer 2

72) point on line: (1,2)

x-intercept: (c,0)

y-intercept: (o,c), c=/=0

Slope-intercept form line equation is y = mx + b, where m is slope and b is y-intercept.

Find the slope of the line m =(y2 - y1)/(x2 - x1)

m = (c - 0) / (o - c)

m = c/ -c = -1

Line equation is y = -x + b

find the b value by substituing (1, 2) in equation

2 = -1 * 1 + b

add 1 to each side

3 = b

The line equation is y = -x + 3

I hope it helps!