SOLUTION: If f(x)=2x^2 -7x+3 find Part A f(2) Part B f(-3) I have tried to solve this by plugging the 2 in for x and for part A came up with -3 and for part B came up with 42. a

Algebra ->  Systems-of-equations -> SOLUTION: If f(x)=2x^2 -7x+3 find Part A f(2) Part B f(-3) I have tried to solve this by plugging the 2 in for x and for part A came up with -3 and for part B came up with 42. a      Log On


   

Question 128655: If f(x)=2x^2 -7x+3 find
Part A f(2)

Part B f(-3)
I have tried to solve this by plugging the 2 in for x and for part A came up with -3 and for part B came up with 42. am I doing this correctly
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
a)

Let's find f(2)

f%28x%29=2x%5E2-7x%2B3 Start with the given function


f%282%29=2%282%29%5E2-7%282%29%2B3 Plug in x=2


f%282%29=2%2A4-7%2A2%2B3 Raise 2 to the 2nd power to get 4


f%282%29=8-7%2A2%2B3 Multiply 2 and 4 to get 8


f%282%29=8-14%2B3 Multiply 7 and 2 to get 14


f%282%29=-6%2B3 Subtract 14 from 8 to get -6


f%282%29=-3 Add -6 and 3 to get -3


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b)

Let's find f(-3)

f%28x%29=2x%5E2-7x%2B3 Start with the given function


f%28-3%29=2%28-3%29%5E2-7%28-3%29%2B3 Plug in x=-3


f%28-3%29=2%2A9-7%2A-3%2B3 Raise -3 to the 2nd power to get 9


f%28-3%29=18-7%2A-3%2B3 Multiply 2 and 9 to get 18


f%28-3%29=18--21%2B3 Multiply 7 and -3 to get -21


f%28-3%29=39%2B3 Subtract -21 from 18 to get 39


f%28-3%29=42 Add 39 and 3 to get 42




So you are correct.