# If xy = 144, x + y = 30, and x > y, what is the value of x – y ?

To find the value of X and Y is simple if X+Y equal 30 than you can take 144 and divide it by 2 since 2 numbers equal 144 and you get 72 then you can change the value of X and Y to get something that equals 72 and still adds to 30 so it would be a Negative and a Positive we do this but subtracting 30 by 72 to get 42 which means one of our variables is 42 and then we do it again 30 minus 42 and we get negative 12 so our variables are 42 and negative 12 or in MX format (42+-12) which equals 30 I’ll leave the rest for you

Source(s): I just know your not gonna pick me

Since xy+144, x+y=30 and x>y, start by assuming they are equal and set each as 15, then shift them apart to find values with a difference of 4. This gives us 17 and 13, but 17*13 is more than 144.
Do the same thing for answer choice B, values with a difference of 6 gives us 18 and 12, but 18*12 is still too big. Answer choice C with a difference of 18 gives us values of 24 and 6. 24*6=144 and we have found our answer.

xy=144
x+y=30
Substitute x=144/y and put it into the second equation
–> 144/y + y=30 multiply by y and you get
–> 144 + y^2 =30*y rearrange to a quadratic equation
–> y^2 – 30y + 144 solve the quadratic equation and get
–> y1=24 and y2= 6
Since x>y this means x=24 , y=6
This means x-y = 24-6= 18

xy=144

x + y=30

(x+y)^2 – 2xy = 900-288=612 = x^2 + y^2

(x-y)^2 = 612 – 288 = 324

Since x > y:

x-y = 18