SOLUTION: given that , 10^0.48 = x,10^0.70 =y and x^z =y^2, then the value of z is a)1.45 b)1.88 c)2.9 d)3.7

Algebra ->  Equations -> SOLUTION: given that , 10^0.48 = x,10^0.70 =y and x^z =y^2, then the value of z is a)1.45 b)1.88 c)2.9 d)3.7       Log On


   



Question 1039520: given that , 10^0.48 = x,10^0.70 =y and x^z =y^2, then the value of z is
a)1.45
b)1.88
c)2.9
d)3.7

Answer by Theo(13342) About Me  (Show Source):
You can put this solution on YOUR website!
you are given that:

x = 10^(.48)
y = 10^(.7)
x^z = y^2.

replace x with 10^(.48) and replace y with 10^(.7) and you get:
(10^(.48))^z = (10^(.7))^2

since (a^b)^c = a^(b*c), you get:

(10^(.48))^z = (10^(.7))^2 becomes 10^(.48*z) = 10^(.7*2)
simplify this to get 10^(.48*z) = 10^(1.4)

this is true if and only if .48*z = 1.4.
solve for z to get z = 1.4/.48 = 2.91666666667
this rounds to z = 2.9

that would be selection c.

you would confirm by replacing z with 2.91666666667 in the original equation to get:

(10^.48)^(2.91666666667) = 25.11886432
(10^.7)^2 = 25.11886436

they're the same, so the the solution is correct.

z = 2.9 rounded to the nearest tenth.