# How do you evaluate #x^3 - 2y^2 - 3x^3 + z^4# if x = 3, y = 5, and z = -3?

##### 1 Answer

Jul 18, 2016

#### Answer:

-23

#### Explanation:

By substituting the given numeric values for x,y and z into the expression.

That is

#(3)^3-2(5)^2-3(3)^3+(-3)^4#

#"------------------------------------------------"#

I'll evaluate each term separately.

#(3)^3=3xx3xx3=9xx3=27#

#2(5)^2=2xx(5xx5)=2xx25=50#

#3(3)^3=3xx(3xx3xx3)=3xx27=81#

#(-3)^4=[(-3)xx(-3)]xx[(-3)xx(-3)]=9xx9=81#

#"-------------------------------------------------"#

Replace these values back into the expression , noting the values which are subtracted.

#rArr27-50-cancel(81)+cancel(81)=27-50=-23#