I see the answers,but where is the problem (equation that needs to be solved)
Answer:
20
Step-by-step explanation:
x = price
y = number of keyboard
xy = 540
(x-2)(y+3) = 540
x = 540/y
==> x = 20
==> y = 27
length : 
Explanation:
use the distance formula : 




Answer:55mm
Explain:I know