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you have the function f(x)=x/5+2x-2

 

a) decide f(20)

f(20)=20/5+2*20-2

4+38=42

 

b) what is x if f(x)=31.   how do i do here??

 Feb 23, 2015

Best Answer 

 #1
avatar+23254 
+5

If  f(x)  = x/5 + 2x - 2

and f(x)  =  31,

then set the two right-sides of the equations equal to each other:     x/2 + 2x - 2  =  31

I would get rid of the fractions first; I would multiply each term by 2:  x + 4x - 4  =  62

Then, simplify the left side:                                                                   5x - 4  =  62

Add 4 to both sides:                                                                                   5x  =  66

Divide by 5:                                                                                                x  =  66/5

 Feb 24, 2015
 #1
avatar+23254 
+5
Best Answer

If  f(x)  = x/5 + 2x - 2

and f(x)  =  31,

then set the two right-sides of the equations equal to each other:     x/2 + 2x - 2  =  31

I would get rid of the fractions first; I would multiply each term by 2:  x + 4x - 4  =  62

Then, simplify the left side:                                                                   5x - 4  =  62

Add 4 to both sides:                                                                                   5x  =  66

Divide by 5:                                                                                                x  =  66/5

geno3141 Feb 24, 2015

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