Question 1119010
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A rectangle has an area of 2x^2 + 2x - 112.
a) If one side is (x -7) cm, show that the perimeter is 6(x +3)cm. 
b) Hence or otherwise, find the range of possible values for x
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(b)
Range?  Possible x values -  first find the roots....
{{{2x^2+2x-112=0}}}
{{{x^2+x-56=0}}}
{{{(x-7)(x+8)=0}}}
Only positive factors allowed.
{{{highlight_green(x>7)}}}



(a)
The other side is {{{(2x^2+2x-112)/(x-7)=2x+16}}}.

Perimetr:  {{{2(2x+16)+2(x-7)}}}

{{{4x+32+2x-14}}}

{{{6x+18}}}

{{{6(x+3)}}}