If 3 times a number is 28 more than its opposite what is the number

n = 7

Step-by-step explanation:

Let n represent the number.  Then 3n = -n + 28, or 4n = 28.

Dividing both sides by 4 yields n = 7.

Check:  "3 times a number" is 3n = 21

The "opposite" of the number is -7.  

If we add 28 to this "opposite," we get 21.  This is correct:  21 = 21

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

slope =   (y2 -y1) ÷ (x2 -x1)

slope = (0 -0) / (-5, -7)

slope = 0 / -12 = 0

the slope of the line is zero.   it is perfectly horizontal.

step-by-step explanation: