Question

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

Answer 1

-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`