Subtracting rational expressions
warm-up
find the least common denominator for the following rational expressions.
18
-5r
r + 7
7-4 72 - 5r+4' 12 - 48-5
x (-1)(r - 4)(r – 5)
(r- 1)(r + )
c (r - 1)(r + 1)(r – 4)(7-5)
(r-1)(r + 1)(r + 4)(– 5)
retry

y - y1 = m(x- x1)

y - (-5) = 2/3(x -0)

y + 5 = 2/3x

y = 2/3x - 5

a 4/6 = 9/12   not proportional

step-by-step explanation:

to find which are not proportional, we can use cross products

if it is true, they are proportional.   if it is not true, they are not proportional.

a 4/6 = 9/12

4* 12 = 6*9

48 = 54

not this is not proportional  

b 2/3 = 12/18  

2* 18 = 3 * 12

36 = 36

this is proportional

c 5/4 = 10/8  

5*8 = 4*10

40 = 40

this is proportional

d 7/5 = 35/25

7*25 = 5 * 35

175 = 175

is proportional

yes

step-by-step explanation:

they have to be opposite and reciprocal of eachother.