ALGEBRA 1
posted by Kayla .
You practice playing your guitar every day. You spend 15 minutes practicing chords and the rest of the time practicing a new song. So the total number of minutes y you practice for the week is given by y=7(15+x), where x is the number of minutes you spend on practicing a new song.
a. Solve the equation for x.
b. How many minutes did you spend on a new song if you practiced 210 minutes last week? 245 minutes? 315 minutes?
is a: x=1/7y15

a. y = 7(15 + x)
y = 105 + 7x
y  105 = 7x
1/7y  105/7 = x
X DOES NOT EQUAL 1/7y  15. You didn't distribute the 7 to 15. Remember to distribute to all on the equation, not just the x!
b. 210 = 105 + 7x
105 = 7x
x = 105/7 = 15 minutes practicing new song 
sorry. x does equal 1/7y  15. but if you only spend 210 minutes practicing that one week, it is impossible for you to practice 245 or 315 minutes on the new song.

A: Solve for the equation for X.
Y=7(15+X)
Y=105+7X
Y105=7X
Y/715=X or 1/7 Y15=X
B: Plug in the number Y as 210, 245, 315
210=7(15+X)
210=105+7X
105=7X
15=X
[That was the example for if you practiced 210 minutes last week.] 
245:
245=105+7X
140=7X
20=X
315:
315=105+7X
210=7X
30=X