Can i get some help pls i don't know how to write this equation

 x = (log(y) /(400 log1.0065) or x = log(initial cost)/1.126

Step-by-step explanation:  Take the log of both sides of your equation:

log(y) = log(400)(1.0065)^x

log (y) = log 400 + log(1.0065)^x

Subtract log(400) from both sides:

log(y) - log 400 = xlog(1.0065)

Divide both sides by log(1.0065)

[log(y) - log(400)]/log(1.0065) = x

Now, if you want to know how many years it will take for the guitar to be worth $200, replace y with 200 and solve.

the least common denominatore of 7 and 2 is 9

step-by-step explanation:

7+2=9

in the attachment.   i didn't see your choices.   the word which means there is choices.

step-by-step explanation:

(x,y)

x tells you how much left or right you go from the origin

y tells you how much down or up you go from the origin

so for example (-3,2), you go left 3 and up twice. i denoted which of the ordered pairs is which in my graph.