Find f(5). f(x) = x2 + 2x A)15 B)20 C)30 D)35
1 answer:
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Answer:
The unknown dimension is 35
Step-by-step explanation:
The perimeter of a rectangle is l+l+w+w or 2l+2w (l=length, w=width)
then we subtract 14 from 84
Let's check our answer
<u>Hope this helps :-)</u>
I'm thinking this is what the problem looks like: 
. The first thing to do is to move the 
over to the other side because it has a common denominator with the other side. Doing that and at the same time combining them over their common denominator looks like this: 
. The best way to solve for x now is to cross-multiply to get 3(4-x)=-4(x-4). Distributing through the parenthesis is 12 - 3x = -4x + 16. Solving for x gives us x = 4. Of course when we sub a 4 back in for x we get real problems, don't we? Dividing by zero breaks every rule in math that there ever was! So, yes, the solution is extraneous.