Question

2. Find the slope of the line described by:
x - 7*y = -6


3. Tell whether the equation: -x + 5*y = -6 represents a direct variation. Explain why/why not.


4. Find the x- and y-intercepts of -x + 2y = 20

Answer 1

2.
x - 7y = -6
x - 7y - x = -6 -x
-7y= -6 -x
(-1) 7y = (-1) (6+x)
7y=x+6
y=1/7x+6/7
The Slope is 1/7

3.
-x + 5y = -6
-x + 5y +x = -6 + x
5y = x -6
y = 1/5x +6
It is NOT a direct variation, because it has a y-intercept.

4.
-x + 2y = 20
-x + 2y + x = 20 + x
2y = x + 20
y = 1/2x +10

find x intercept find y intercept
y = 1/2x +10 y = 1/2x +10
(0) = 1/2x +10 y = 1/2(0) +10
0= 1/2x+10 y= 0 + 10 = 10
0 -10 = 1/2x+10 - 10
-10 = 1/2x (both sides times 2)
-20 =x

x intercept = -20 y intercept =10