Question

A line passes through the point (8,9) and has a slope of 5/4.

Write an equation in slope-intercept form for this line.

Answer 1

The equation is:
y
=
5
4
x
−
13

Step-by-step explanation:
The slope-intercept form of a straight line is
y
=
m
x
+
c

In this case we have a point,
(
x
,
y
)
and the slope,
m
so all we need is a value for
c
.
Substitute into
y
=
m
x
+
c

−
3
=
5
4
(
8
)
+
c

−
3
=
10
+
c

c
=
−
13

Answer 2

y= 1 1/4x -1

Step-by-step explanation:

first, plot the point (8,9)

now lets plot some more points, points that are part of this line.

rise/run 5/4, so 5 up and 4 to the right, and a point on the left, 5 down 4 to the left. I'll do that again, 5 down and 4 to the left. In other problems, do this until you find the y intercept. (which ended up being (0,-1)

slope-intercept form is mx+b

m is the slope, b is the y-intercept

in this case b is -1

the y-intercept coordinate will always have the x value being 0 so it would be (0, varies) which in this case it is (0, -1)

now lets find the value of m.

since the slope, 5/4, can not be simplified to a whole number, it'll just be 1 1/4.

m ends up being 1 1/4.

fill it in, now.

y= 1 1/4x -1

-----------------

the process to find an equation knowing only a point and the slope for future reference:

plot the points until you find a y intercept (sometimes you have to make a line and find a fraction for a y intercept)

simplify the slope

fill it into mx+b

m=slope

b= y-intercept

hopefully this was helpful