SOLUTION: Let f(x)=2x^2-5x and find: A: f(-2) B: f(0) C: 2f(x) D: f(2x)

Algebra ->  Functions -> SOLUTION: Let f(x)=2x^2-5x and find: A: f(-2) B: f(0) C: 2f(x) D: f(2x)      Log On


   

Question 88483This question is from textbook College Algebra
: Let f(x)=2x^2-5x and find:
A: f(-2)
B: f(0)
C: 2f(x)
D: f(2x) This question is from textbook College Algebra

Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
A)
f%28x%29=2x%5E2-5x Start with the given polynomial


f%28-2%29=2%28-2%29%5E2-5%28-2%29 Plug in x=-2


f%28-2%29=2%284%29-5%28-2%29 Raise -2 to the second power to get 4


f%28-2%29=8-5%28-2%29 Multiply 2 by 4 to get 8


f%28-2%29=8--10 Multiply 5 by -2 to get -10


f%28-2%29=18 Now combine like terms


B)

f%28x%29=2x%5E2-5x Start with the given polynomial


f%280%29=2%280%29%5E2-5%280%29 Plug in x=0


f%280%29=2%280%29-5%280%29 Raise 0 to the second power to get 0


f%280%29=0-5%280%29 Multiply 2 by 0 to get 0


f%280%29=0-0 Multiply 5 by 0 to get 0


f%280%29=0 Now combine like terms

C)
f%28x%29=2x%5E2-5x Start with the given polynomial

2%2Af%28x%29=2%282x%5E2-5x%29 Multiply the entire polynomial by 2

2%2Af%28x%29=2%2A2x%5E2-2%2A5x Distribute

2%2Af%28x%29=4x%5E2-10x Multiply


D)
f%28x%29=2x%5E2-5x Start with the given polynomial

f%282x%29=2%282x%29%5E2-5%282x%29 Plug in x=2x

f%282x%29=2%284x%5E2%29-5%282x%29 Square 2x

f%282x%29=8x%5E2-5%282x%29 Multiply 2 and 4x%5E2

f%282x%29=8x%5E2-10x Multiply 5 and 2x