How do you solve x^3 + 2y^3 for x = 7 & y = 1?

2 Answers
Apr 5, 2018

345

Explanation:

Just by replaicing the values in x and y:

x^3+2y^3

7^3+2·1^3=345

Apr 5, 2018

345

Here's how I did it:

Explanation:

Your expression is x^3 + 2y^3 and you know that x = 7 and y = 1. We just plug in these values for x and y, and then we simplify:

(7)^3 + 2(1)^3

7^3 is the same thing as (7)(7)(7), or 343.

Now, for 2(1)^3, we have to look this order of operations called PEMDAS. This stands for:
P arentheses
E xponents
MD Multiplication/Division
AS Addition/Subtraction

In your expression 2(1)^3, the first thing we need to do is take care of the exponent. (1)^3 is the same thing as (1)(1)(1), which is just 1.

So now we do 2(1), which is 2.


Finally we add 2 with 343 (from earlier) to get the final simplification of 345.