Algebra 2
posted by Ann on .
Exponential Notation
Evaluate the following:
x^3+y^2 for x=3 and y=4
I don't understand how to solve this equation. I solved it and got 11 as my answer but the books answer is 26 15/16
Thanks For Your Help

x^3 + y^(2)
to evaluate means you substitute the value of x and y which are given in the problem.
first, recall some laws of exponents. if a term is raised by a negative number, it is also equal to its reciprocal raised to the that number but positive in sign. for example,
5^(3) = (1/5)^3
thus we can actually rewrite this equation as
x^3 + (1/y)^2
substituting x = 3 and y = 4,
(3)^3 + (1/4)^2
(3)*(3)*(3) + (1/4)*(1/4)
27 + 1/16
26 15/16
hope this helps~ :) 
thanks so much :)) That was really helpful. Just one quick question. How did you get 15/16?

you can rewrite 27 as 26 16/16 (since 16/16 is just equal to 1). thus,
26 16/16 + 1/16
26 + (161)/16
26 15/16 
ohh okk thanks so much :)