Question

Find two numbers with a sum of 15 and a difference of 4​

Answer 1

Explanation:

X+Y=15

X-Y= 4

=> X-Y+2Y=15

<=> 4+2Y= 15

=> Y= 5,5

=>X = 15-5,5=9,5

Vậy 2 số đó là 9,5 và 5,5

Answer 2

The numbers are

5.5 and 9.5,

Explanation:

If the numbers are x and y:

x + y = 15

x - y = 4

If we add these 2 equations we eliminate y, so

2x = 19

x = 19/2 = 9.5.

Substituting in the first equation for x:

9. 5 + y = 15

y = 15 - 9.5 = 5.5