Question

Find x3 - 2y2 - 3x3 + z4 if x = 3, y = 5, and z = -3.

-185

-77

-23

85

Answer 1

Why not substitute and evaluate?

Answer 2

Well, \[3^{3} - 2y ^{2} + -3^{4} ?\]

Answer 3

@tkhunny

Answer 4

Sorry, -2(5)^2

Answer 5

Where did the z go?
Substitute the value for 'y', too. Get them all!

Answer 6

x^3 - 2y^2 - 3x^3 + z^4

x = 3

(3)^3 - 2y^2 - 3(3)^3 + z^4

y = 5

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

z = -3

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

Just like that.

Answer 7

3^3 = 27

Answer 8

2(5)^2 = 20

Answer 9

3(3)^3 = 81?

Answer 10

-3^4 = 81

Answer 11

Not quite. Let's try that again.

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

3^3 = 27 -- You got that.

27 - 2(5)^2 - 3(3)^3 + (-3)^4

2(5^2) = 2*25 = 50

27 - 50 - 3(3)^3 + (-3)^4

3(3^3) = 81 -- You got this one.

27 - 50 - 81 + (-3)^4

(-3)^4 = +81 -- Careful with the notation. This MAY be different from -3^4. These two expressions are not ALWAYS the same.

27 - 50 - 81 + 81

Answer 12

-23?

Answer 13

Why do you doubt? :-)

Answer 14

idk. lol

Answer 15

You were a lot of help, thanks.