Home > Algebra > Function Notation

How do you evaluate the polynomial #-3x^3+8x^2-4x-6# for #x=4# and for #x=-4#?

Answer 1

Eli Assouline

#-86" and "330#

#"substitute the given values for x into the expression"#

#-3xx(color(red)(4))^3+8xx(color(red)(4))^2-4xxcolor(red)(4)-6#

#=(-3xx64)+(8xx16)+(-4xx4)-6#

#=-192+128-16-6#

#=-86#

#-3xx(color(red)(-4))^3+8xx(color(red)(-4))^2-4xxcolor(red)(-4)-6#

#=(-3xx-64)+(8xx16)+(-4xx-4)-6#

#=192+128+16-6#

#=330#

By signing up, you agree to our Terms of Service and Privacy Policy

Answer 2

Abigail Allen

To evaluate the polynomial -3x^3 + 8x^2 - 4x - 6 for x = 4 and for x = -4, substitute the values of x into the polynomial expression and calculate the result.

For x = 4: -3(4)^3 + 8(4)^2 - 4(4) - 6 = -3(64) + 8(16) - 16 - 6 = -192 + 128 - 16 - 6 = -66

For x = -4: -3(-4)^3 + 8(-4)^2 - 4(-4) - 6 = -3(-64) + 8(16) + 16 - 6 = 192 + 128 + 16 - 6 = 330

By signing up, you agree to our Terms of Service and Privacy Policy

Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.