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

The numbers are

5.5 and 9.5,

Step-by-step 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

Step-by-step 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

(sin 42)/31. = sinx)/37

sinx = 37 (sin42)/31

= 37× 0.66/31 = 0.787

x= 51.9

other angle opposite to y = 180-51.9-42

= 180- 93.9 =86.1

so

sin42)/31 = sin 86.1)/y

0.021 = 0.997 /y

y= 0.997/0.021 =47.47