average of 15 and 25 is equal to the average of 17 and x?

Question

 show me some basic so that ii can slove more

Answer 1

(15+25)/2=(17+x)/2

because the denominators are equal the numerators must be equal

15+25=17+x

40=17+x

40-17=x

23=x, or...

(15+25)/2=40/2=20

20=(17+x)/2

20*2=17+x

40=17+x

40-17=x

23=x again

Answer 2

The best way to answer is to look at the difference between the numbers 15 and 17.  Since 17 is 2 more than 15, the number that gets added to 17 must be 2 less than 25, or 23.

 

Let's check and see...

15+25=40÷2=20

17+23=40÷2=20