Let f be a function defined by f:x-- 5x2+2; xER

  1. Find the image of 3 under f.
  2. Find f(3).f(2)
  3. Find x such that f(x) =22

for finding the image of 3 under f, we take x=3

5(3*3) + 2 = 47 Ans.= 47

similarly f(3) = 47

f(2) = 22

hence, f(3).f(2) = 47*22 =1,034

now, we have to find f(x)=22

= 5x^2 +2=22

= x^2 = 4

= x= +2 or - 2

thumbs up plz if u r satisfied ...

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Let f be a function defined by fx 5x²+2 find the image of 3 under f
  • 1
3.
(i) For f(3) = 5*3^2 + 2
                 = 45 + 2
                 = 47
(ii) For f(2)= 5*2^2 +2
                 = 22

f(2)*f(3) = 47 * 22
             =1034

(iii) For f(x) = 22

22 = 5x^2 + 2
20 = 5x^2
4   = x^2
x   = +2 (or) -2

I hope you understand now.....
Thank you....
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