Iwill give 11. = 18 to y 12. z to 4= 13. 9 to 15= 15; y

Step-by-step explanation:

18^y = 4/6        Take the log of both sides

log(18^y) = log(4/6)

log(18^y) = y * log(18)

log (4/6) = - 0.17609

y * log(18) = y * 1.25527

So

y = - 0.17609 / 1.25527

y = - 0.14056

Check

18^-0.14056 = 0.6661 which is close enough to 0.666666666

z^4 = 8/5                        Take the log of both sides.

log(z^4) = log(8/5)          Simlplify the left. Take the log of the right.

4 * log(z) = 0.20416        Divide by 4

log(z) = 0.20416 /4

log(z) = 0.051029          Take the antilog of both sides.

z = 10^(0.051029)

z = 1.12467

Check

1.12467 ^ 4 = 1.6 which is what it should be.

I can't really make out the third one.