If the sum of two number is 19. their difference is 3. what are the numbers?

x, y - the numbers

x + y = 19

x - y = 3        add both sides of the equations

2x = 22      divide both sides by 2

x = 11

Substitute the value of x to the first equation:

11 + y = 19     subtract 11 from both sides

y = 8

i found two solutions,   n = 2 • ± √3 = ± 3.4641

step-by-step explanation:

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