Math

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Find the value of x.
The area of a rectangle = 105
The length is 2x+1
Width is x
__________________________________

I tried solving it :
Arec = l x w
105 = (2x+1)x
105 = 2x^2 + x
0= 2x^2 + x - 105

This is where I get stuck on...

  • Math -

    quadratic equation
    x = [ -1 +/- sqrt (1+840)]/4
    = [ -1 +/- 29 ]/4
    = 28/4 forget negative solution
    = 7

    or
    (x - 7) (2x + 15) = 0

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