algebra 2 problem

Question

I need to find the value of f (1.6) and (1.9)

 

(x)=x^5-x^4+6x^3-4x^2-18x+8; [1.6, 1.9]

Answer 1

Given Equation:

f(x) = x⁵ – x⁴ + 6x³ – 4x² – 18x + 8

Find value of f (1.6) and f (1.9)?

This problem deals with substitution and simplification approaches.

PEMDAS method will be used for simplification purposes.

Red ink represents what gets simplified first based on PEMDAS.

Solving for f (1.6):

f (1.6) = (1.6)⁵ – (1.6)⁴ + 6(1.6)³ – 4(1.6)² – 18(1.6) + 8

f (1.6) = 10.486 – 6.554 + 6(4.096) – 4(2.56) – 28.8 + 8

f (1.6) = 10.486 – 6.554 + 24.576 – 10.24 – 28.8 + 8

f (1.6) = 10.484 + 18.022 – 10.24 – 20.8 = -2.532

Solving for f (1.9):

f (1.9) = (1.9)⁵ – (1.9)⁴ + 6(1.9)³ – 4(1.9)² – 18(1.9) + 8

f (1.9) = 24.761 – 13.032 + 6(6.859) – 4(3.61) – 34.2 + 8

f (1.9) = 24.761 – 13.032 + 41.154 – 14.44 – 34.2 + 8

f (1.9) = 24.761 + 28.122 – 14.44 – 26.2 = 12.243

Answer 2

Hi there! When a question asks find the value of f(x), you need to plug in the X value (value in the parentheses; in this case it would be 1.6 and 1.9) into the equation. So the equation for f(1.6) would be 1.6^5-1.6^4+6(1.6)^3-4(1.6)^2-18(1.6)+8. Using PEMDAS you would now solve the equation. This method would also work for f(1.9). Hope this helps!